Luminous Landscape Forum
Raw & Post Processing, Printing => Printing: Printers, Papers and Inks => Topic started by: JB Rasor on October 10, 2014, 03:51:54 am
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I've been printing photos, on the Epson 3880, using the advice Michael and Jeff have advocated (that is if an image is below 360ppi, up sample to 360ppi, and if it is over 360 up sample to 720ppi).
However, I've seen individuals advocate down sampling to achieve a larger print size...using Photoshop instead of Lightroom. In other words, taking a resolution down to 120ppi to achieve a 40 inch print for example. Is it best to always aim for 360 or 720ppi when Epson printers are concerned? Or is down sampling something to consider?
I'm doing an MFA in photography right now, and the individual suggesting down sampling is the head equipment tech (printers, etc.) I'm thinking he is wrong, but is he?
Thanks everyone!
JB Rasor
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I've been printing photos, on the Epson 3880, using the advice Michael and Jeff have advocated (that is if an image is below 360ppi, up sample to 360ppi, and if it is over 360 up sample to 720ppi).
Hi JB,
In general (depending on the driver settings), that is correct. If you don't resample then the printer driver will (to either 360 PPI, or 720PPI with the finest detail setting on). The algorithms that the printer driver uses are made for speed, not for quality, so you can do a better job with dedicated resampling. That has the added benefit that you can 'output sharpen' at the final output pixel size.
Lightroom usually does a better resampling job than Photoshop, unless you use dedicated resampling (Photozoom Pro, Perfect Resize) and sharpening (Topaz Detail, FocusMagic) plug-ins in Photoshop.
Cheers,
Bart
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Hi JB,
Bart, Michael and Jeff are correct.
Printing at a resolution of 120 will show degraded image quality. As a student in digital imaging, however, you should not just take anyone's word for it. These things are so easy to test for oneself. Do what the printer tech recommended, look at the results on paper compared with the preferred way of doing it and examine the prints to see if you can tell the difference. I'll bet comparing 120 with 360 you really will see it.
I use an Epson 4900 and before that a 3800, a 4800 and a 4000, as well as all the corresponding versions in their time of Lightroom and Photoshop; I periodically run sanity checks on resolution outcomes. I can print down to 180 and get barely acceptable results. Below this I find quality becomes unacceptable. Upwards of 240 is usable and for Epson professional printers, 360 or 720 as they recommend is optimal - doing the up-sizing in Lightroom.
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I've been printing photos, on the Epson 3880, using the advice Michael and Jeff have advocated (that is if an image is below 360ppi, up sample to 360ppi, and if it is over 360 up sample to 720ppi).
However, I've seen individuals advocate down sampling to achieve a larger print size...using Photoshop instead of Lightroom. In other words, taking a resolution down to 120ppi to achieve a 40 inch print for example. Is it best to always aim for 360 or 720ppi when Epson printers are concerned? Or is down sampling something to consider?
I'm doing an MFA in photography right now, and the individual suggesting down sampling is the head equipment tech (printers, etc.) I'm thinking he is wrong, but is he?
Thanks everyone!
JB Rasor
The decision on 360ppi or 720ppi is reasonable. However, if you have not selected 'Finest Detail' in the print driver, the driver will not use the 720ppi, but will downres it to 360. Conversely, if you have select Finest Detail and send it 360ppi, it will uprez it to 720....which could have been done much better on the computer.
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Thanks very much guys. That clears up a lot. Mark, I'll definitely try some test prints and see what the results look like.
John, I haven't been using the Finest Detail check box, even when printing at 720ppi. I'm assuming I should start checking that box when I do up sample to 720ppi via the Lightroom print module? However, leave it unchecked when printing at 360ppi? Does that sound correct?
Thanks again! Have a great weekend everyone!
JB
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I'm assuming I should start checking that box when I do up sample to 720ppi via the Lightroom print module? However, leave it unchecked when printing at 360ppi? Does that sound correct?
Correct. Leaving the 'finest detail' box unchecked will make the printer driver always resample to 360 PPI (unless output is already at that resolution). checking that box will always resample to 720 PPI (unless output is already at that resolution).
Cheers,
Bart
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Correct. Leaving the 'finest detail' box unchecked will make the printer driver always resample to 360 PPI (unless output is already at that resolution). checking that box will always resample to 720 PPI (unless output is already at that resolution).
Cheers,
Bart
From what I've read, if one is looking for a set-it-and-forget-it option, if you always send 720ppi (for any print size) and click finest detail, there is nothing detrimental happening to your print output. Of course it slows down the processing/print process a bit.
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However, I've seen individuals advocate down sampling to achieve a larger print size...using Photoshop instead of Lightroom. In other words, taking a resolution down to 120ppi to achieve a 40 inch print for example. Is it best to always aim for 360 or 720ppi when Epson printers are concerned? Or is down sampling something to consider?
JB Rasor
Not sure this was specifically addressed.. but I would NEVER advocate resampling a photo to a lower resolution in order to print larger. This makes no sense at all. As a general practice you should (if we're talking Epson printers), resample up to the nearest of these integers before sending to print: 120/180/240/360/720. Or resample yourself all the way to 360ppi if you wish. For example, If you have a 144ppi image at say 40x60 inches, I would never advocate resampling to 120ppi at the same size.. you'd be much better off upsampling to 180. No sense throwing away pixels.
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I expect the tech is just expressing it poorly. You would never actually "down-rez" for printing (reduce the total # of pixels in the image), but if you increase the print size the pixels/inch will indeed decrease. Thus, an image that measures 2400 x 3000 pixels is 300 ppi when printed 8 x 10" but 150dpi when printed 16 x 20". But, this is not down-rezzing, it's just arithmetic.
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You're probably right Peter, that the tech wasn't clarifying his comments, rather just showing me the ropes. He has no idea if I have a printing background or not. But that topic I think I have a good handle on now.
However, the Finest Detail checkbox is throwing me for a loop. Am I correct in saying that: If I have an image that is 480ppi, but I upsample to 720ppi in the Lightroom print module, it will still print at 360ppi because I haven't checked the Finest Detail Box?
Is the image than effectively being downsampled in the print pipeline, or has Lightroom done an upsample and the printer is simply printing at 360ppi?
I'm probably making it more confusing than it needs to be, but I always heard Finest Detail wasn't for photographs but vector graphics.
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Hi,
Epson is printing at 360PPI unless you check finest details in which case it prints at 720 PPI.
So the rules are simple:
- If you have less than 360 PPI native resolution upres to 360 PPI using a good algorithm and print without finest detail.
- If you have more than 360 PPI native resolution upres to 720 PPI using a good algorithm and print with finest detail checked.
The reason is that you want to print at either 360 PPI or 720 PPI, and would use a good algorithm, instead letting the printer driver rescale the image using a quick and dirty algorithm. But you may need good vision and/or a loupe to see the difference :-)
You're probably right Peter, that the tech wasn't clarifying his comments, rather just showing me the ropes. He has no idea if I have a printing background or not. But that topic I think I have a good handle on now.
However, the Finest Detail checkbox is throwing me for a loop. Am I correct in saying that: If I have an image that is 480ppi, but I upsample to 720ppi in the Lightroom print module, it will still print at 360ppi because I haven't checked the Finest Detail Box?
Is the image than effectively being downsampled in the print pipeline, or has Lightroom done an upsample and the printer is simply printing at 360ppi?
I'm probably making it more confusing than it needs to be, but I always heard Finest Detail wasn't for photographs but vector graphics.
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However, the Finest Detail checkbox is throwing me for a loop. Am I correct in saying that: If I have an image that is 480ppi, but I upsample to 720ppi in the Lightroom print module, it will still print at 360ppi because I haven't checked the Finest Detail Box?
Yes!
Is the image than effectively being downsampled in the print pipeline, or has Lightroom done an upsample and the printer is simply printing at 360ppi?
When Lightroom upamples to 720 PPI (and optionally sharpens at that resolution), the printer driver will downsample again to 360 PPI (and lose most of the sharpening or, what's worse, create artifacts) when the 'Finest detail' option is not selected.
I'm probably making it more confusing than it needs to be, but I always heard Finest Detail wasn't for photographs but vector graphics.
That misunderstanding was propagated for a long time (see here (http://www.luminous-landscape.com/forum/index.php?topic=54798) and here (http://www.luminous-landscape.com/forum/index.php?topic=77949) for how some of the insights developed), until people started to actually try it. The point is that the difference for regular image content may be small, but it does allow to gain resolution for fine detail, especially after sharpening at 720 PPI.
Cheers,
Bart
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Yes!
When Lightroom upamples to 720 PPI (and optionally sharpens at that resolution), the printer driver will downsample again to 360 PPI (and lose most of the sharpening or, what's worse, create artifacts) when the 'Finest detail' option is not selected.
Cheers,
Bart
Perhaps interesting to debate, that IF one chooses to only print at 360ppi (with no FinestDetail box checking), and if the native image for the given print size is above 360ppi, in these instances is it better to send 360ppi out of LR, or leave at the native resolution? Ie. I assume in this instance that LR would do a better job of throwing away pixels than would the printer?
for example, I suppose one could find themselves in a situation presented with eg. a 380ppi image and decide that uprezzing to 720 might not be worthwhile/noticeable benefit.
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Perhaps interesting to debate, that IF one chooses to only print at 360ppi (with no FinestDetail box checking), and if the native image for the given print size is above 360ppi, in these instances is it better to send 360ppi out of LR, or leave at the native resolution? Ie. I assume in this instance that LR would do a better job of throwing away pixels than would the printer?
for example, I suppose one could find themselves in a situation presented with eg. a 380ppi image and decide that uprezzing to 720 might not be worthwhile/noticeable benefit.
Hi,
The short answer is that LR is almost certainly going to do a better job of down-sampling than a simpler resampling method as employed by the printer driver/pipeline. And it additionally allows to add sharpening after the resampling operation.
However, personally I would never throw away real resolution (the bit above 360 PPI). I see no reason, especially when upsampling to 720 PPI might even improve resolution of the data below 360 PPI (which would require special resampling software such as Photozoom Pro or Perfect Resize, that adds (edge) resolution that exceeds the native file resolution).
Cheers,
Bart
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Perhaps interesting to debate, that IF one chooses to only print at 360ppi (with no FinestDetail box checking), and if the native image for the given print size is above 360ppi, in these instances is it better to send 360ppi out of LR, or leave at the native resolution? Ie. I assume in this instance that LR would do a better job of throwing away pixels than would the printer?
for example, I suppose one could find themselves in a situation presented with eg. a 380ppi image and decide that uprezzing to 720 might not be worthwhile/noticeable benefit.
i suggest you test this for yourself. Just discussing 380 over 360 is pointless.
For me, for my customers, i go for 720 and fine details on except if the ppi of the chosen printsize is lower than 360. How much lower is also based on the image quality as i perceive this. Note i print with epson4900 and epson9900, with Lightroom as my print application. This is based on my experience and evaluations with my customers.
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Hi,
The short answer is that LR is almost certainly going to do a better job of down-sampling than a simpler resampling method as employed by the printer driver/pipeline. And it additionally allows to add sharpening after the resampling operation.
However, personally I would never throw away real resolution (the bit above 360 PPI). I see no reason, especially when upsampling to 720 PPI might even improve resolution of the data below 360 PPI (which would require special resampling software such as Photozoom Pro or Perfect Resize, that adds (edge) resolution that exceeds the native file resolution).
Cheers,
Bart
Theoretically, a 380ppi image upsampled to 720ppi, has 90%+ of pixels manufactured by lightroom, to then be sent with PR at 720ppi. a 380ppi downsampled to 360ppi is removing pixels to print at 360ppi. I wonder if there are instances/image types where the upsampling and higher resolution benefits could be outweighed by lower (360ppi) input/print resolution that has no software-interpolated pixels?
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Theoretically, a 380ppi image upsampled to 720ppi, has 90%+ of pixels manufactured by lightroom, to then be sent with PR at 720ppi. a 380ppi downsampled to 360ppi is removing pixels to print at 360ppi. I wonder if there are instances/image types where the upsampling and higher resolution benefits could be outweighed by lower (360ppi) input/print resolution that has no software-interpolated pixels?
I think the only way to answer this question reliably on a case-specific basis is to try both and see which looks better. After trying a number such cases you may be able to develop a "general rule".
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Theoretically, a 380ppi image upsampled to 720ppi, has 90%+ of pixels manufactured by lightroom, to then be sent with PR at 720ppi. a 380ppi downsampled to 360ppi is removing pixels to print at 360ppi.
Don't think that small amounts can do no damage. Even de-/in-creasing the image size by 1 pixel, will mean that 100% of the pixels will be recalculated/resampled. Depending on the quality of the resampling algorithm, that may reduce quality. It will probably not mean the end of the world for most subjects, but why reduce the quality to begin with?
Upsampling will also lead to recalculation of existing pixels, and the creation of additional new ones, but it may also lead to the possibility to use more sharpening at a smaller scale which will be beneficial for the perceived sharpness. If dedicated upsampling software is used you even (measurably) gain additional (edge) resolution, it adds quality.
I wonder if there are instances/image types where the upsampling and higher resolution benefits could be outweighed by lower (360ppi) input/print resolution that has no software-interpolated pixels?
An example I can think of is when the number of pixels in one dimension exceeds the quantity of pixels that the printer can print in the width of its feed mechanism. But that is a mechanical reason. Quality wise, more pixels usually means smoother gradients, (if needed with added fine dithering or noise) and the possibility of better sharpening.
The only possible quality benefit could be to create a very specific color that the printer driver can dither slightly more accurately with the number of ink droplets that fill a 360 PPI pixel, instead of a 720 PPI pixel, although a good printer driver will use error diffusion that utilizes 4 neighboring 720 PPI pixels to create the same overall color.
Of course fewer pixels means slightly faster printing, which would benefit 360 PPI printing a bit, but it remains to be seen where the bottleneck is (the slowest interface, probably reading from disk).
Cheers,
Bart
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I see this on this board over and over so I am just going to relay what Epson briefed a military program using their technology. This is back a few years when the maximum resolution was 2880 x 1440, K3 inks and 3.5picoliter minimum droplet volumes.
These were the relevant notes I took:
1. If you wish to preclude the printer driver from operating on your data prior to calculating the dithering pattern, the input image sample frequency should be an even multiple of 60ppi. Hence 180ppi, 240pp, 300ppi...
2. Continuous tone printers that put down a consistent number of dots per linear inch across the entire printed area will re-sample the input data to the output frequency. Epson Stylus printers do not operate that way. There is no 1 to 1 correspondence. It looks at chunks of 60x60 pixels of the input image and translates that to the image area to be covered by that chunk and based on the media selection and driver settings, calculates the dither pattern.
3. Epson Stylus printers do not have a native resolution as such. The resolutions listed for the printer indicate the physical constrainst on how tight the droplet pattern. A listed resolution of 1440dpi does not mean the printer WILL lay down 1440 dots per inch across the entire printed area, only that the algorithm is free to use up to 1440 different droplets per linear inch. The goal is to achieve the appearance of continuous tone so the algorithm varies the location, volume and color of droplets as required based on the constraints provided.
4. The maximum pattern density is limited by the media type based on the ink load the media can take and the spread of the droplets. Plain paper, for example, is both poor at holding ink and has a high drop spread. Therefore, selecting that media type will preclude the printer using any of the higher resolution droplet patterns.
5. Apparent sharpness is obtained using the tightest droplet patterns on media with minimum droplet spread. However, smooth, glossy media that exhibits the least dot spread also have a lower ink load limit than most heavy weight matte papers which exhibit higher droplet spreads. The printer accounts for this by varying the number of drops and volume of each drop in calculating the pattern.
6. The best output is obtained by sending the printer the best image representation possible. Do not expect upsampling of an image to result in superior output, unless that upsampling serves the purpose of actually improving the input data. Specifically, once the input data sample frequency passes approximately 240 - 300ppi, any increase in sample frequency that does not involve an increase in actual quality of the input data is no longer productive. The algorithm merely operates on the data given in conjunction within the constrains of the media selection to calculate the best droplet pattern.
7. Beyond 360ppi the media properties end up being the limiting factor. For example, while Epson Exhibition Fiber has great droplet hold (low spread), it can't take the ink load necessary to take advantage of ever tighter patterns. [I asked about smaller droplets and he conceded that that is the goal. To tighten the pattern by using smaller droplets. He still was not committal about any apparent improvements from the printing process being able to reproduce additional detail.]
I've been printing photos, on the Epson 3880, using the advice Michael and Jeff have advocated (that is if an image is below 360ppi, up sample to 360ppi, and if it is over 360 up sample to 720ppi).
However, I've seen individuals advocate down sampling to achieve a larger print size...using Photoshop instead of Lightroom. In other words, taking a resolution down to 120ppi to achieve a 40 inch print for example. Is it best to always aim for 360 or 720ppi when Epson printers are concerned? Or is down sampling something to consider?
I'm doing an MFA in photography right now, and the individual suggesting down sampling is the head equipment tech (printers, etc.) I'm thinking he is wrong, but is he?
Thanks everyone!
JB Rasor
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I see this on this board over and over so I am just going to relay what Epson briefed a military program using their technology. This is back a few years when the maximum resolution was 2880 x 1440, K3 inks and 3.5picoliter minimum droplet volumes.
Sadly, this only perpetuates the myth. We know better now. It is better to send 360PPI than any other multiple of 60. That's the old myth. And yes, it IS better to upsample to 360 (or 720 using finest detail) than letting the driver deal with non-standard rez.
Sorry, but it's my experience the military doesn't always get the correct info about much of anything that doesn't actually shoot.
:~)
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Hello!
This is fascinating. I am working on printing some 16mp images on a 9890 to40x60". I'm trying to figure the best workflow to getting the best blow up.
I hadn't thought about targeting the output resolution i.e 360dpi. (720dpi would be impossible)
That being said. If I upres my images to the final print size @360dpi, is there any benefit "when?" the upsize occurs?
Example.
These images have had a fair amount of processing. Lightroom adjustments, Upright, Noise reduction, Clarity, Sharpening, cloning, spot healing, some external plug-ins like NIK Define. I am even playing with adding real grain to give a realistic grain pattern to the 40x60"
So, I have been upsizing via the latest PS CC to the print dimension @240dpi. A far stretch. But that is the size I need for the show.
I'm wondering if upresing would be better done before one of the heavy images processes, like clarity, or noise reduction? I think Sharpening would be best at the end.
Thanks to you guys I will be much more careful in targeting my final DPI to 360.
In fact I think I may have output my final Tiff files @240, but ended up in Lightroom trying to print them with a smaller border (minor enlarging), essentially, screwing up the 240 dpi output.
You can learn a lot on this forum.
Thanks
Max
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Sadly, this only perpetuates the myth. We know better now. It is better to send 360PPI than any other multiple of 60. That's the old myth. And yes, it IS better to upsample to 360 (or 720 using finest detail) than letting the driver deal with non-standard rez.
Sorry, but it's my experience the military doesn't always get the correct info about much of anything that doesn't actually shoot.
:~)
I take no offense, I was just relaying what was divulged during a program kickoff meeting.
I do ask where the definitive information that it is better to up sample to 360ppi or 720ppi originates? Is this something divulged by Epson publicly or privately based on knowledge of the dithering algorithm or testing or does this come from your considerable experience?
Thanks!
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... I am working on printing some 16mp images on a 9890 to40x60". I'm trying to figure the best workflow to getting the best blow up.
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Generally: uprez and then perform output sharpening just prior to printing, has been the perceived best practice. It is the way the Lr and Qimage do it for you. There are several reasons. If you do a search, you find it was discussed a lot.
[ppi, not dpi]
Brian A
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I take no offense, I was just relaying what was divulged during a program kickoff meeting.
I do ask where the definitive information that it is better to up sample to 360ppi or 720ppi originates?
Well, a lot of the discussion occurred here on LuLa and that lead me to do the research to write an article in Digital PhotoPro magazine called The Right Resolution (http://www.digitalphotopro.com/item/12871-the-right-resolution).
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I do ask where the definitive information that it is better to up sample to 360ppi or 720ppi originates?
Extensive testing, and the fact that the printer driver tells the application that is using the printer driver what resolution it expects to be sent.
Sending a regular pixel pattern to the printer will result in resampling/aliasing artifacts, unless exactly 360 or 720 PPI is used on Epsons, 300 or 600 PPI on Canon/HP and others. The principle of native printer resolution has been known for a long time, and has e.g. been used by Qimage since 1998.
Otherwise the printer driver (supported by the OS on Mac) resamples to 360 PPI (or 720PPI when finest detail is selected). This is a separate issue from the 60 dot dither pattern that is used to create intermediate ink colors. The resampling method that the printer driver uses is relatively simple (usually bi-linear), and it doesn't allow to output sharpen after resampling, so it's best to resample first, then sharpen, then send to the printer.
Cheers,
Bart
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Extensive testing, and the fact that the printer driver tells the application that is using the printer driver what resolution it expects to be sent.
Sending a regular pixel pattern to the printer will result in resampling/aliasing artifacts, unless exactly 360 or 720 PPI is used on Epsons, 300 or 600 PPI on Canon/HP and others. The principle of native printer resolution has been known for a long time, and has e.g. been used by Qimage since 1998.
Otherwise the printer driver (supported by the OS on Mac) resamples to 360 PPI (or 720PPI when finest detail is selected). This is a separate issue from the 60 dot dither pattern that is used to create intermediate ink colors. The resampling method that the printer driver uses is relatively simple (usually bi-linear), and it doesn't allow to output sharpen after resampling, so it's best to resample first, then sharpen, then send to the printer.
Cheers,
Bart
So it is empirically derived and not definitive. Fine. I certainly respect Jeff and your experience and results!
But the massive assumption being made, with no reference to back it up, is that the printer driver re-samples the original data to something whether 360, 720 or something else which can't be learned empirically!
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So it is empirically derived and not definitive. Fine. I certainly respect Jeff and your experience and results!
But the massive assumption being made, with no reference to back it up, is that the printer driver re-samples the original data to something whether 360, 720 or something else which can't be learned empirically!
There are ways to learn it, e.g. this user (http://forum.luminous-landscape.com/index.php?topic=54211.msg444116#msg444116) found out that 359 PPI and 361 PPI get resampling artifacts, 360 PPI doesn't. He also mentions a comment by Eric Chan (member of the Lightroom development team) about resampling to 360 PPI, and here (http://blog.kasson.com/?p=1896) some more examples from printing at 240 PPI compared to software upsampled 360 PPI. There are more threads and examples, but I don't have the time to collect them for you.
As said, printing a line or dot grid will tell if resampling is happening, and if head alignment and paper transport is well adjusted one can derive from the interference pattern what has happened. You can already simulate that by resizing such a grid in e.g. Photoshop with bilinear resampling, and compare it to what the printer produces.
Cheers,
Bart
P.S. I've attached a resampling test image that should produce aliasing in proportion to the number of pixels resize difference.
P.P.S. A zoneplate target (https://www.dropbox.com/s/e3wmc4lqxervncb/Rings.png?dl=0) will allow to detect all sorts of aliasing issues at various angles, but it may be harder to pinpoint the exact factors involved due to printers using (stochastic) dithering patterns.
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For the HP Z3100 driver I tested it in downsampling as discussed here:
http://forum.luminous-landscape.com/index.php?topic=54798.60
Alternating lines were lost of the 1200 PPI test target due to aliasing in the conversion to 600 PPI, the same for a 600 PPI test target to 300 PPI. The route from the application to the printer starts with a straight downsampling, most likely nearest neighbour before the dithering etc builds the print data. The difference with upsampling is better algorithms used for the last in today's drivers.
Printing from Qimage with its resampling and sharpening off. I doubt I still have the prints here but could check.
It is as empirical as any test done to check a theory.
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
December 2014 update, 700+ inkjet media white spectral plots
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It is as empirical as any test done to check a theory.
Indeed, it's a bit like gravitation. Nobody tells you what is really is, but the empirical evidence and some clever deduction produces a workable theory (proposed by Einstein) that even allows to navigate in outer space.
Cheers,
Bart
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There are ways to learn it, e.g. this user (http://forum.luminous-landscape.com/index.php?topic=54211.msg444116#msg444116) found out that 359 PPI and 361 PPI get resampling artifacts, 360 PPI doesn't. He also mentions a comment by Eric Chan (member of the Lightroom development team) about resampling to 360 PPI, and here (http://blog.kasson.com/?p=1896) some more examples from printing at 240 PPI compared to software upsampled 360 PPI. There are more threads and examples, but I don't have the time to collect them for you.
As said, printing a line or dot grid will tell if resampling is happening, and if head alignment and paper transport is well adjusted one can derive from the interference pattern what has happened. You can already simulate that by resizing such a grid in e.g. Photoshop with bilinear resampling, and compare it to what the printer produces.
Cheers,
Bart
That is what empirical means...by observation or experience. You try different things and look at the output and choose the input that gives the most favorable output. We guide hyper-velocity vehicles not by known math, but by empirical results built up over decades of testing.
But there is a big difference between saying upsizing to 360 or 720ppi produces the best results based on mountains of testing and the printer driver resamples to 360 or 720ppi. The first is true based on observation, but the second can not be determined true by observation. It is a theory that might be true. The reason I point this out is that it is actually unnecessary for a dithering algorithm to resample to some base to calculate the dithering pattern. We do it by matching input and output area and converting directly.
Having started with the 1994 Seiko Epson Stylus Color printer and currently still stuck on an R2400, I have always fed my printer 360ppi when printing for maximum quality. I will upsample to 360ppi and even down sample to it. Depending on the original image, I find that upsampling say a 430ppi image to 720ppi does not provide increased benefit than down sampling it well to 360ppi. Though I might upsample to to 720 if stating closer to 500ppi.
Assuming a 10% drop size spread, then to print at 720 would require drops on paper of 35.28 microns each which relates to a 32.07micron drop diameter. Calculating out the volume of a droplet would be about 17picoliter. Hence, the 3.5picoliter dropsize allows for printing at 720dpi. Conversely, if I did the quick and dirty math correctly, then 3.5ml drops would equate to roughly 19 microns in diameter would allow printing at roughtly 1350dpi. Of course, the paper has to be able to take that kind of ink load and the printer have that type of horizontal and vertical mechanical precision.
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I see the R2400 was introduced around 2005. In docs Epson quotes resp. 3 and 3.5 picoliter for the dropsize, that is the minimum droplet size, usually 2 other sizes above that size. In the highest print resolution setting only the minimum droplet size is used. On the old Epson 9000 the print resolution was documented as 1440 dpi, in practice the printer laid down 720 dpi, the next row shifted half the droplet pitch and another 720 dpi was laid down. Whether that could be qualified as 1440 dpi was questionable. The minimum droplet size was about 10 picoliter, variable droplet sizes still in the early stages of development. Whether droplets of one ink channel are allowed to overlap or not is also open for debate. In the past the ink amount laid down with different print resolutions required different custom profiles. Today for several models this is compensated it seems. either in dithering or media preset ink limits. So what you might conclude of your empirical testing with the R2400 may not work for general conclusions on the behavior of today's printer/driver models.
In the thread I gave the URL for you can read that Jeff Schewe even found a 1440 PPI input printer quality setting in Epson x900 models for the Epson Proofing White SemiMatte, a very high quality paper. Most likely the driver reporting to Lightroom. http://forum.luminous-landscape.com/index.php?topic=54798.180 The Epson engineers probably thought it was worth it with that quality of paper. I found an 1200 ppi input resolution in an older HP Z3100 driver but it was gone with the next driver version installed. Both at the edge of what can be gained in image quality I guess.
My downscale aliasing test was done to check whether the theory of fixed input resolutions was sound. A theory developed as no hard information from manufacturers reaches the users. A theory that forms the base of the extrapolation functions Mike Chaney added to Qimage since more than a decade. So here the theory existed and I made the test to check it. So I wrote "as empirical" lifting that proof somewhat above the empirical evidence of print quality observations.
What is interesting is the QTR driver based on Gutenprint/Gimpprint. When asked Roy Harrington wrote it did not have that kind of input resolution steps. I can imagine that guys like Robert Krawitz used another approach for that print engine. We do not argue that a driver has to have certain input resolution steps but find evidence that OEM drivers have them and that they force the data through less than ideal resampling algorithms before the real driver job begins. Edit: well I checked my memory of this and found a reply by Roy that QTR resamples everything thrown at it to 720x720 before it goes into the dithering phase for the printer resolutions set. An avant la lettre and hard coded equivalent for the Bart van der Wolf / Jeff Schewe approach.
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
December 2014 update, 700+ inkjet media white spectral plots
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But there is a big difference between saying upsizing to 360 or 720ppi produces the best results based on mountains of testing and the printer driver resamples to 360 or 720ppi. The first is true based on observation, but the second can not be determined true by observation.
Hi,
In the way that we have iron clad proof (e.g. Epson documentation from the printer driver programmers), no, you are right. However, there's that thing popularly called the duck test (https://en.wikipedia.org/wiki/Duck_test). People like Jim Kasson whom's blog I linked to, even dared to call his duck (http://blog.kasson.com/?p=548) 'nearest neighbor' resampling, because that's the closest resemblance to what the printer he tested produced. Maybe in the mean time that has been improved to bi-linear, but that's not the relevant point.
Not only can we do much better resampling ourselves, but we are using inductive reasoning to qualify the method used, without hard proof, just duck proof, highly probable. The conclusion that resampling is used, is consistent with the aliasing artifacts formed by that method. Hence we call the duck, 'resampling'.
It is a theory that might be true. The reason I point this out is that it is actually unnecessary for a dithering algorithm to resample to some base to calculate the dithering pattern. We do it by matching input and output area and converting directly.
Sure, many methods can be used, but given the 'quality' of the output, it's unlikely that they used something more sophisticated. Besides, it's easier and faster to present the dithering algorithm a known quality (maximum resolution 180/360 cycles per inch, or 360/720PPI, potentially 41 percent higher diagonally) of data, to allow for the seamless successive printhead passes. Complexity usually results in added (maintenance and buffer memory) cost and slower performance, which are things that are not popular in production environments.
Cheers,
Bart
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Not only do I not doubt Jeff and Bart's recommendations, I've been using them since before I knew who Jeff and Bart were.
My comments only relate to what we know versus what we think. There is no need to say that the printer resamples to X to make the point that sending the printer Xppi results in the best output. That has been demonstrated empirically in response to a lack of definitive answers from Epson. I would suspect Epson was leery of saying too much in 1994 when no one really had much high density data. Let's face it, if people are shooting a 2.1MP $7000 Nikon D1 do you really want to tell they they are woefully short on data to use the printer at it's most effective. But along the way, I think it has been irresponsible of Epson and other manufacturers not to specifically document how to get the best output from their printers.
I see the R2400 was introduced around 2005. In docs Epson quotes resp. 3 and 3.5 picoliter for the dropsize, that is the minimum droplet size, usually 2 other sizes above that size. In the highest print resolution setting only the minimum droplet size is used. On the old Epson 9000 the print resolution was documented as 1440 dpi, in practice the printer laid down 720 dpi, the next row shifted half the droplet pitch and another 720 dpi was laid down. Whether that could be qualified as 1440 dpi was questionable. The minimum droplet size was about 10 picoliter, variable droplet sizes still in the early stages of development. Whether droplets of one ink channel are allowed to overlap or not is also open for debate. In the past the ink amount laid down with different print resolutions required different custom profiles. Today for several models this is compensated it seems. either in dithering or media preset ink limits. So what you might conclude of your empirical testing with the R2400 may not work for general conclusions on the behavior of today's printer/driver models.
In the thread I gave the URL for you can read that Jeff Schewe even found a 1440 PPI input printer quality setting in Epson x900 models for the Epson Proofing White SemiMatte, a very high quality paper. Most likely the driver reporting to Lightroom. http://forum.luminous-landscape.com/index.php?topic=54798.180 The Epson engineers probably thought it was worth it with that quality of paper. I found an 1200 ppi input resolution in an older HP Z3100 driver but it was gone with the next driver version installed. Both at the edge of what can be gained in image quality I guess.
My downscale aliasing test was done to check whether the theory of fixed input resolutions was sound. A theory developed as no hard information from manufacturers reaches the users. A theory that forms the base of the extrapolation functions Mike Chaney added to Qimage since more than a decade. So here the theory existed and I made the test to check it. So I wrote "as empirical" lifting that proof somewhat above the empirical evidence of print quality observations.
What is interesting is the QTR driver based on Gutenprint/Gimpprint. When asked Roy Harrington wrote it did not have that kind of input resolution steps. I can imagine that guys like Robert Krawitz used another approach for that print engine. We do not argue that a driver has to have certain input resolution steps but find evidence that OEM drivers have them and that they force the data through less than ideal resampling algorithms before the real driver job begins. Edit: well I checked my memory of this and found a reply by Roy that QTR resamples everything thrown at it to 720x720 before it goes into the dithering phase for the printer resolutions set. An avant la lettre and hard coded equivalent for the Bart van der Wolf / Jeff Schewe approach.
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
December 2014 update, 700+ inkjet media white spectral plots
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Jeff Schewe even found a 1440 PPI input printer quality setting in Epson x900 models for the Epson Proofing White SemiMatte, a very high quality paper.
Actually, a fellow from Epson told me that they added that specific settings for proofing papers for the express purpose of being able to print actual halftone dots. And I tested it and could not find any benefit for printing regular photos at that setting. The reason I tested it was to determine of LR's max rez should go from 720 to 1440 ppi.
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Well, a lot of the discussion occurred here on LuLa and that lead me to do the research to write an article in Digital PhotoPro magazine called The Right Resolution (http://www.digitalphotopro.com/item/12871-the-right-resolution).
Jeff,
That link appears to be broken.
Regards,
Bill
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That link appears to be broken.
Hum...well go to http://www.digitalphotopro.com click on the Workflow link under Technique tab and scroll down to The Right Resolution article.
Maybe I miscopied the url when I added the url link...Not sure but DPP may be doing something with their urls, but http://www.digitalphotopro.com/technique/photography-workflow/the-right-resolution works for me.
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Hum...well go to http://www.digitalphotopro.com click on the Workflow link under Technique tab and scroll down to The Right Resolution article.
Maybe I miscopied the url when I added the url link...Not sure but DPP may be doing something with their urls, but http://www.digitalphotopro.com/technique/photography-workflow/the-right-resolution works for me.
With respect to the linked article, you wrote: The Epson pro printers' print heads have a reported output resolution of 360/720 dpi, depending on the print mode.
Where has this been reported? I fear this is one of those statements that someone says and it gets repeated over and over until the conjecture is believed to be fact. In over 20 years of using Epson Stylus printers and working directly with Epson, I have never heard them make this claim. What they do claim is that the printers have the ability to print X number of different droplets per linear inch depending on the printer and printer settings. Epson printers print with variable drop volumes with variable spacing.
Later, the following statement appears: The people at Epson say that the print driver doesn't do the re-sampling, and since the application sending the print doesn't do the resampling unless asked to do so, the resampling must be happening in the print pipeline.
This is an assumption that the image is resampled which may or may not occur. But I assure you it is not the Windows GDI doing it if it does occur. Either the printer driver does it or it doesn't occur. In fact, on Windows, Epson installs it's own printer port and not only bypasses GDI, but also includes it's own spooler.
Considering that you write that Epson denies the the driver resamples the data and we know that a dithering algorithm does not require the data be resampled to a specific base resolution, is it more likely that the data isn't resampled or some other mystery cuplrit in every operating system just happens to resample to a somewhat bizzare 360/720ppi? Otherwise, print quality would be different on every OS! And if Both major OS's resampled the data to 360/720 why would Canon, HP and every other printer manufacturer design their printers to use 300ppi where now they would have to resample the data back down from the previous re sampling. [ADDED] Of course, the other alternative is that Epson lied and the driver does re-sample!
All that said, I generally send 360ppi data to my Epson printers because I believe (but do not know) it provides the best quality.
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With respect to the linked article, you wrote: The Epson pro printers' print heads have a reported output resolution of 360/720 dpi, depending on the print mode.
Where has this been reported?
It's reported to the system...it's well known and documented. You can prove it to yourself by saving images as PDFs from the Mac print dlog and then checking the resulting resolution. If you don't believe me, Mike Chaney has written about this...while Epson doesn't include this in written docs, it ain't rocket science to prove...
This is an assumption that the image is resampled which may or may not occur.
This is exactly what an Epson product manager said to me when asked is the Epson driver "resampled" and image that wasn't sent as 360/720 PPI.
Clearly an image sent as anything other than 360/720 to an Epson Pro printer is modified and can result in some image artifacts (particularly stair-stepping). Whether or not the image is resampled has not been confirmed by either Apple nor MSFT...Epson says no...and I know for a fact neither Photoshop nor Lightroom does. So if not the driver nor the app, where is the "resampling" occur?
Wherever it occurs, it's clear that the resampling (if it occurs) is substandard. Some say Bilinear while other say Nearest neighbor. Which ever, it tends to suck...
I'm still of the mind that the driver doesn't "resample" but merely sends the the raw image data to a complex dithering algorithm that tends to add artifacts if the data isn't reported as either 360 PPI (or 720 PPI if finest detail is selected).
Also note that Epson printers that do not have finest details as a driver option (the Epson consumer printers) can't report 720 and thus can't benefit from resolutions beyond 360 PPI.
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With respect to the linked article, you wrote: The Epson pro printers' print heads have a reported output resolution of 360/720 dpi, depending on the print mode.
Where has this been reported?
It is reported by the printer driver to the program that interrogates the driver. The PPI that's being fed back, depends on the driver settings, e.g. paper/ink combinations and resolution settings (Epson's 'Finest Detail' option to allow 720 PPI', Canon usually specifies in the driver what's used, e.g. 600PPI).
Later, the following statement appears: The people at Epson say that the print driver doesn't do the re-sampling, and since the application sending the print doesn't do the resampling unless asked to do so, the resampling must be happening in the print pipeline.
This is an assumption that the image is resampled which may or may not occur. But I assure you it is not the Windows GDI doing it if it does occur. Either the printer driver does it or it doesn't occur. In fact, on Windows, Epson installs it's own printer port and not only bypasses GDI, but also includes it's own spooler.
Things differ between Windows and Mac platforms. On Macs part of the print processing is delegated to OS related functions that are used for resampling (see this thread (http://forum.luminous-landscape.com/index.php?topic=90225.msg737098#msg737098)), while on Windows it's typically a printer driver operation. On Windows it is possible to use a 16-bit/channel print output (e.g. Canon supports that with their XPS drivers), I believe on Macs the maximum is currently 8-b/ch. So there are differences.
Cheers,
Bart
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I've been asked to come here and chime in. I see that the thread has branched out in many different directions so I'm not sure exactly which aspect to address, so I'll address the original question. The original question, as I see it, was regarding whether or not it ever makes sense to downsample to something like 120 PPI for something like an Epson printer. Downsampling to 120 PPI means that you started with something higher than that and you are downsampling to 120 PPI. As an example, you start with an image that happens to be 217 PPI at the intended print size. So is there any benefit to downsampling from 217 PPI to 120 PPI versus upsampling from 217 PPI to 360 or 720?
I would say no. The reason being, whenever you downsample, you are throwing away data. That's data you cannot get back and at something as low as 120 PPI, the "lost data" will be evident in the print if you compare to one that was upsampled instead to say, 360 or 720 PPI. The more data you start with, the more "detail" the viewer will perceive (up to a point of course, depending on viewing conditions, device limitations, etc.). On the other side of the fence, you would choose to upsample to 360 or 720 not because you think you are "gaining data", but because those resolutions align nicely with the dot patterns used by an Epson printer and, being multiples, align well with those dot patterns and produce fewer artifacts. As an added benefit, you are using the data you have and not throwing anything away when you upsample.
When talking about upsampling to 360 versus 720, I've found that most printers/papers can render detail at a maximum of somewhere between that range. In other words, some detail can be rendered higher than 360 but probably not as high as 720. It's not straightforward because it depends on the printer you are using, the paper you are printing on, the driver settings, and even the color you are testing. Generally speaking, if you are printing a high res image and that image already has higher than 360 PPI at the intended print size, printing at 720 versus 360 will yield a little better minute detail. But you'll probably have to put your nose almost to the paper to see it. That's why I often say that printing at 360 PPI is fine for large prints and 720 more appropriate for smaller ones because those smaller ones might undergo closer scrutiny. Nothing wrong with printing at 720 PPI for everything, but you may never see the benefit on a 40x30 hanging on a wall.
Mike
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On the other side of the fence, you would choose to upsample to 360 or 720 not because you think you are "gaining data", but because those resolutions align nicely with the dot patterns used by an Epson printer and, being multiples, align well with those dot patterns and produce fewer artifacts. As an added benefit, you are using the data you have and not throwing anything away when you upsample.
Hi Mike,
Thanks for commenting here. An additional benefit of upsampling rather than throwing away data, is that one can output sharpen at the larger size, i.e. more precise and probably use a bit higher amount as well. With Qimage Ultimate and your DFS algorithm used for Smart output sharpening, it can be pushed further because DFS doesn't produce halos.
You mention the alignment with the dot patterns used, and all evidence points in the direction of the dither pattern expecting either 360 or 720 PPI input, or it will first resample to that. Yet there are also some who question whether resampling actually takes place, even though the aliasing patterns of test prints point towards resampling (given the periodic aliasing artifacts that are perfectly consistent with resampling). Also the printer driver reports back what PPI it wants to receive.
Because you've studied the printer driver API in more detail, and may have spoken with insiders at Epson/Canon, do you have any additional 'proof' you are allowed to share that resampling is what the printer driver will do, instead of some sort of dithering that happens to produces 'resampling artifacts' (which would be strange for a stochastic dither pattern, unless very poorly designed).
When talking about upsampling to 360 versus 720, I've found that most printers/papers can render detail at a maximum of somewhere between that range. In other words, some detail can be rendered higher than 360 but probably not as high as 720. It's not straightforward because it depends on the printer you are using, the paper you are printing on, the driver settings, and even the color you are testing. Generally speaking, if you are printing a high res image and that image already has higher than 360 PPI at the intended print size, printing at 720 versus 360 will yield a little better minute detail.
Yes, that's the overall consensus nowadays. In my experience, even some very nice matte surfaces (like Canson Infinity Baryta Photographique, with a satin surface) can retain these high resolutions. Of course, a good profile will help the printer to send the right amount of ink to avoid too much ink diffusion. Maybe it would even be a nice addition for Qimage to offer some sort of control to allow tweaking of sub-optimal paper profiles for the best ink load that offers the largest gamut with high densities but minimum ink useage.
But you'll probably have to put your nose almost to the paper to see it.
Ha, you can leave it up to us pixel peeping photographers to do just that! ;)
That's why I often say that printing at 360 PPI is fine for large prints and 720 more appropriate for smaller ones because those smaller ones might undergo closer scrutiny. Nothing wrong with printing at 720 PPI for everything, but you may never see the benefit on a 40x30 hanging on a wall.
And viewing distance will quickly kill our ability to see the detail anyway. However, don't underestimate the benefits of being able to do better output sharpening(!), which translates to more than just the detail between 360 and 720 PPI. The Modulation Transfer Function (MTF) curve of the entire image will be lifted when the finest details are sharpened. The entire image will 'pop' more, even at larger viewing distances.
Cheers,
Bart
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As I've said, I send 360ppi to my Epson and have done so all the way back to the 1994 Epson Stylus Color printer. For smaller prints for which I have more data than 360ppi, I sometimes upsample to 720ppi.
I don't know the Mac OS, but on Windows, the Graphics Device Interface (GDI) is basically concerned with screen draws. There is obviously the printer function calls necessary to facilitate printing, but the actual data handling and conversion is done by the driver (more a full featured program in Epson's Case). The Windows GDI printer calls are here (https://msdn.microsoft.com/en-us/library/windows/desktop/ff686800%28v=vs.85%29.aspx). The only thing that comes into play is the DeviceCapabilities function call the application makes to populate the INTERNAL printing dialog boxes. One value it can request is DC_ENUMRESOLUTIONS in which it passes back the resolutions capable by the printer. However, I've never seen an application actually use this function and instead requires you to go into the into the Epson printer properties box, not part of GDI,...something like this:
(http://lh6.ggpht.com/_sZCMHC4TbRc/TGPE0WHp8EI/AAAAAAAAA4A/SdxmPmj2YPo/image15%5B1%5D.png?)
As we are all aware, Epson does not present an option to change 'resolution' directly, but based on combination of settings like Media Type, Print Quality and Finest Detail checkbox affect a change in printer quality indirectly to 720x720, 1440x720, 2880x1440, etc.
Question: You are saying if I write a program that issues a DeviceCapabilities function call to the Epson printer, it will report back 360 and 720, 1440 or whatever depending on the printer model?
DWORD DeviceCapabilities(
_In_ LPCTSTR pDevice,
_In_ LPCTSTR pPort,
_In_ WORD DC_ENUMRESOLUTIONS,
_Out_ LPTSTR pOutput,
_In_ const DEVMODE *pDevMode
);
Jeff, unfortunately, on the the Windows platform I don't see how one could save the image to PDF without specifically giving the application a resolution setting or printing to PDF which also entails setting the output parameters. There does not seem to be a method on Windows to use printing settings for the Epson and then save as PDF instead except maybe printing to a FILE port and looking at the printer output.
Finally, someone mentioned a 359pp, 360ppi, 361ppi test resulting in some aliasing artifacts. Has this test been done at 239,240,241 or 479,480,481 to see if the same occurs?
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I don't know the Mac OS, but on Windows, the Graphics Device Interface (GDI) is basically concerned with screen draws. There is obviously the printer function calls necessary to facilitate printing, but the actual data handling and conversion is done by the driver (more a full featured program in Epson's Case). The Windows GDI printer calls are here (https://msdn.microsoft.com/en-us/library/windows/desktop/ff686800%28v=vs.85%29.aspx). The only thing that comes into play is the DeviceCapabilities function call the application makes to populate the INTERNAL printing dialog boxes. One value it can request is DC_ENUMRESOLUTIONS in which it passes back the resolutions capable by the printer.
As we are all aware, Epson does not present an option to change 'resolution' directly, but based on combination of settings like Media Type, Print Quality and Finest Detail checkbox affect a change in printer quality indirectly to 720x720, 1440x720, 2880x1440, etc.
Question: You are saying if I write a program that issues a DeviceCapabilities function call to the Epson printer, it will report back 360 and 720, 1440 or whatever depending on the printer model?
Hi,
I'm not 100% sure if that's the function that, amongst others, Qimage uses, but it could well be the one. There could be other mechanisms besides the Windows GDI that may be involved, and the printer driver itself might also have some directly accessible functions.
Finally, someone mentioned a 359pp, 360ppi, 361ppi test resulting in some aliasing artifacts. Has this test been done at 239,240,241 or 479,480,481 to see if the same occurs?
I don't have an Epson printer, so I cannot test that specifically for you. If you use the test file I attached to my earlier response (post #26 (http://forum.luminous-landscape.com/index.php?topic=94151.msg806353#msg806353)), tag (no resampling, only tagging) a copy with the PPI you want to test, and send it to the printer, it would give you the answer.
The file is 720 pixels wide, so it should print as 720/239=3.013 inches, 720/240=3.0 inches, 720/241=2.988 inches, when not resampled. Now try and force it to print as 3.0 inches exactly (you might want to try both with and without the 'Finest detail' option on), and watch what happens. Compare that to printing it to exactly 1 inch, at 720 PPI with 'finest detail' switched on. Same for the 479/480/481 scenario.
I would also be interested to see the actual results that the Epson driver produces, with the relevant driver settings used (so others can repeat and compare the experiment, to rule out specific printer issues like head alignment). Few people post images of their findings, which makes it difficult to discuss and compare. Jim Kasson's scanned output in his blog is a fine exception to that.
Using a paper with relatively low ink diffusion characteristic is of course helpful.
Cheers,
Bart
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I'm not 100% sure if that's the function that, amongst others, Qimage uses, but it could well be the one. There could be other mechanisms besides the Windows GDI that may be involved, and the printer driver itself might also have some directly accessible functions.
I'm surprised Qimage actually interacts with the printers. Even Photoshop doesn't. I haven't seen an application that actually worked that way since Windows 3.1!! Most applications require you to utilize the printer driver/application to make settings changes beyond maybe setting the number of copies. Though Photoshop does take the current paper size setting from the printer, but not much else that I can tell.
I'm also surprised that Epson's driver/application is smart enough not to override the Qimage settings with it's own stored defaults/last used settings in the driver.
I don't have an Epson printer, so I cannot test that specifically for you. If you use the test file I attached to my earlier response (post #26 (http://forum.luminous-landscape.com/index.php?topic=94151.msg806353#msg806353)), tag (no resampling, only tagging) a copy with the PPI you want to test, and send it to the printer, it would give you the answer.
The file is 720 pixels wide, so it should print as 720/239=3.013 inches, 720/240=3.0 inches, 720/241=2.988 inches, when not resampled. Now try and force it to print as 3.0 inches exactly (you might want to try both with and without the 'Finest detail' option on), and watch what happens. Compare that to printing it to exactly 1 inch, at 720 PPI with 'finest detail' switched on. Same for the 479/480/481 scenario.
I would also be interested to see the actual results that the Epson driver produces, with the relevant driver settings used (so others can repeat and compare the experiment, to rule out specific printer issues like head alignment). Few people post images of their findings, which makes it difficult to discuss and compare. Jim Kasson's scanned output in his blog is a fine exception to that.
Using a paper with relatively low ink diffusion characteristic is of course helpful.
Once I get my installation of Photoshop back printing from my Jeff inspired experiment trying to get the Epson output to file via printing to the Epson 3880 on FILE: printer port hosed it up, I will give this a try. Most likely I will use some EEF scraps so that is about as good as it gets for sharpness.
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I'm surprised Qimage actually interacts with the printers. Even Photoshop doesn't. I haven't seen an application that actually worked that way since Windows 3.1!! Most applications require you to utilize the printer driver/application to make settings changes beyond maybe setting the number of copies. Though Photoshop does take the current paper size setting from the printer, but not much else that I can tell.
The minimum borders/margins are also reported and used.
I'm also surprised that Epson's driver/application is smart enough not to override the Qimage settings with it's own stored defaults/last used settings in the driver.
What is to override? This is the requested input resolution (in ppi), it is not like you are trying to set the output resolution (dpi). But, if you do not check Finest Detail, 720 ppi is overridden.
There is a similar method (function) in Java, if I remember correctly.
Brian A
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What is to override? This is the requested input resolution (in ppi), it is not like you are trying to set the output resolution (dpi). But, if you do not check Finest Detail, 720 ppi is overridden.
There is a similar method (function) in Java, if I remember correctly.
Brian A
Quite frankly, everything, If Qimage does not bypass the front end to the driver/app.
With respect to your second sentence, that is the question that is being investigated and has never been definitively confirmed. If the Epson driver was requesting data in a specific resolution, I would have expected that this would have been documented long ago. There has been speculation about this issue since 1994 and a definitive answer this simple seems unlikely to have gone undocumented, especially as it would have eliminated a lot of consternation and crap loads of wasted paper and ink used for testing.
Since I haven't programmed anything in about 6 years, I have to load the C++ development environment back on my system to see what the Epson returns to a resolution request. I suspect a null string, as I expect the driver front end is going to want complete control, but will gladly jump for joy if it returns 360 and 720 as there would at least be some hint that a resample is being requested. I will also be disappointed if the 3880 returns:
360x360
720x720
1440x720
1440x1440 and
2880 x 1440.
This will be useless in this investigation as it will just represent printer output 'resolutions' that would populate a selection dialog and not be indicative of any re-sampling.
And it makes zero sense that if the driver requires the data in a specific resolution that A) Epson would not want to do the resampling to ensure the best quality possible, or B) The application would not do it as the best vehicle and that it would be left to the OS to resample the data.
[Added Clarification]
The return values of the DeviceCapabilities API call are not requirements for anything for the application or GDI to do. If the DC_ENUMRESOLUTIONS request comes back 150, 300 and 600 dpi, that does not mean the data sent to the printer must be a raster image in that resolution. It is information intended for the application to present to the user as a option if its using it's own printer dialog. Photoshop does not use this resolution data and requires the user to set these properties in the printer driver settings application. Both Photoshop and the OS is completely agnostic as to what resolution and Epson printer is going to print at. This is a throwback to the old days when printers had their own RIP and special processors. Now, all the data is processed on the PC side and transferred to the printer.
Bottom line: If you print from Photoshop a 4x5 image at 360ppi, no matter how you set the printer driver, what get's sent to the driver is identical. Only the data output by the driver and sent via the port to the printer will be different. The only thing that changes is how the data is handled by the driver and the mechanical machinations of the printer itself. The point of an outboard RIP is to give the user control on over how the data is handled. But then, you are bypassing the driver and sending the data via the output port directly to the printer. Again, the Application and OS are ignorant of those handling options.
Hence, either the data is resampled by Epson in the driver or it's not resampled at all! There is no mystery component in every OS mucking with your data.
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This has been excellent info. I needed to print 34x25ish" from 16mpx 4500x3200 files.
Taking the advice here, I uprezed my files to 360 dpi for printing out of LR5.
I tried Perfect resize 9, because they have the "fractal" algorithm.
Also PS CC 2014.
What I found is, with some noise reduction first, Perfect Resize gave a rather dabbled pattern. irregular dabs. A bit smoother than PS. I think PS is more accurate to the original file.
Perfect Resize is a bit more arty, watercolor like. Not a bad thing.
So, hopefully I'm getting the absolute best large print from these steps.
I don't think you would be missing anything using the latest PS uprezing.
I'm going to try some 34x48" prints next.
Even though my initial file size is not optimal, (waiting for my 50mpx Sony a7rII) I think the added viewing distance at 34x48" will balance out the lack of resolution. We will see!
This is the fun part of having a 9890!
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I'm surprised Qimage actually interacts with the printers.
Qimage does not bypass the printer driver (if that's what you mean), it interrogates it and sends it various settings. It can store different settings e.g. for different papers, and then populates the necessary fields of the driver, before sending it the resampled data. For the resampling it first asks which resolution the printer expects to receive, and then resamples the image to match those expectations. That also involves things like asking for print margins, the real ones based on printable area, because it needs to know the actual output size and then uses the PPI info to resample pixel perfect results, and sharpens that (based on the amount of resampling, thus respecting the original resolution that's available) before setting the printer driver settings and outputting the data stream to the driver.
Qimage is not a RIP in the traditional sense, but a image resampling and print queue manager that interacts with the printer driver (receiving and sending of parameters, and outputting image data).
Cheers,
Bart
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I thought Mike could shed a light on how Qimage interacts with the Windows drivers but he kept that part disguised so far. Might be on purpose, Lightroom does not have that level of interaction. The relation with the settings is also kept in the saved Qimage log files but with for example changes in driver versions the choices can get corrupted. With the HP Z drivers there were more issues in the past as they were less Windows compatible according Mike. I think this thread had its answers for the OP and did not change my perspective on the driver requested input resolutions. The thread may not satisfy the curiosity of programmers but the described tests and reported printer's practice give enough indications it isn't BS.
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
December 2014 update, 700+ inkjet media white spectral plots
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.. I uprezed my files to 360 dpi for printing out of LR5.
Why would you do that? Why not let Lr handle it?
Brian A
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Go back to reply #19
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Go back to reply #19
I am not questioning the 360 ppi, I am questioning uprezing in Ps to print from Lightroom, which, unless I am misreading it, appears to be what was done. When all that needs to be done is to check the Resolution box in Lightroom and set it to 360 ppi.
Brian A
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OK, there's so much cross-talk and so many applications at play in this thread it's hard to keep track of the conversation. But yes, I agree with what you say about doing it in LR. And it works very well.
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OK, there's so much cross-talk and so many applications at play in this thread it's hard to keep track of the conversation. But yes, I agree with what you say about doing it in LR. And it works very well.
Ditto!
I read your post Brian but Mark answered the question - your reply clarified what you really meant and it is absolutely correct.
There is no need to to uprez in Ps if one can do it in Lightroom (easier too).
Tony Jay
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Because I was uprezing from around 4500x3200 to 12,200x XXX. I experimented with the different options and found uprezing in the current PS CC 2014.2 using Preserve detail setting to produce the most acceptable file to print. In fact I just printed a 34" x 48" this way and it looks great.
The original fine was very sharp and clean to start with. I do a bit of noise reduction first with NIK Define. Then Image Resize.
I like Perfect Resize but it is not as detailed as PS. I found that Lightroom 5.7 does not use as good an algarythm as the latest PS. LR does seem to lag a bit with matching PS features, i.e. Contentaware, etc.
Maybe in LR6 the upresing will be equal.
Understand, I'm doing a pretty big jump. Maybe for going from 8x10 to 11x14 or 16x20 LR5 is fine.
I did 100% print outs using LR5, PS CC Preserve Detail, and Perfect Resize. All to 360dpi. They are close, but to my eye, PS looked less "altered." Perfect resize has a watercolor like dappled "grain."
LR5 had more jaggies, that is why I think it is using an older re-sampling algorithm. Remember a couple releases ago PS updated their image Resize algorithm.
It is subtle but at a 34x48" print you can see some difference around the edges.
Also, my workflow, I can examine the uprez on screen prior to wasting a 4 foot print.
But I may try the Perfect resize 9 again for certain images that do not have fine grain.
As soon as I get a roll of 44" Glossy, I'll try a 42"x64" print.
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Qimage does not bypass the printer driver (if that's what you mean), it interrogates it and sends it various settings. It can store different settings e.g. for different papers, and then populates the necessary fields of the driver, before sending it the resampled data. For the resampling it first asks which resolution the printer expects to receive, and then resamples the image to match those expectations. That also involves things like asking for print margins, the real ones based on printable area, because it needs to know the actual output size and then uses the PPI info to resample pixel perfect results, and sharpens that (based on the amount of resampling, thus respecting the original resolution that's available) before setting the printer driver settings and outputting the data stream to the driver.
Qimage is not a RIP in the traditional sense, but a image resampling and print queue manager that interacts with the printer driver (receiving and sending of parameters, and outputting image data).
Cheers,
Bart
Yeah, I got that. To bypass the driver you would have to convert the data to the 'machine's native language. I was not speaking to Qimage specifically, but applications of all types in general.
My main points were:
1. Resolutions returned by a printer in response to a query are not input requirements, but options for output.
2. There is no secret component within all the OSes that mysteriously re-samples raster data as it passes from application to printer driver. Therefore, any re-sampling occurs in the application (not likely) or in the driver (denied by Epson).
3. The Epson driver allows only certain options to be set by the application directly. Output resolution is generally not one of them (mainly because it interacts with the media type selection). Neither is color handling. It expects the user to set these in the printer settings front end to the driver or will pull them from the default settings (at least on Windows).
4. If it was something as simple and obvious as the Epson driver requiring specific input resolutions, that would have been discovered about 30 minutes after the original dither algorithm appeared in 1994 in the original Stylus Color printer.
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4. If it was something as simple and obvious as the Epson driver requiring specific input resolutions, that would have been discovered about 30 minutes after the original dither algorithm appeared in 1994 in the original Stylus Color printer.
So, you are still doubting that the print driver reports to the OS it's "desired" resolution? While not specifically "documented" it's been well known that both Mac and Windows print drivers report their "desired" resolution to the OS. With Epson pro printers that resolution is 360PPI unless finest detail is selected. With Canon/HP it's either 300PPI or 600PPI depending on the the driver setting. In both Epson's case, depending on the media setting the reported rez can be 1440 and for Canon/HP it can be 1200PPI.
It seems you want to chase this issue down a rabbit hole...sorry, not really interested. I did my research and wrote my article and I'm pretty much done with it. Bottom line is if the input rez if under 360/300 (Epson.Canon-HP) then upsample to 360PPI. If above 360/300, upsample to 720 (Epson with finest detail) or 600PPI (for typical Canon or HP settings).
Not sure why this is so hard to test and understand.
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My main points were:
1. Resolutions returned by a printer in response to a query are not input requirements, but options for output.
If a specific resolution is not supported, then that limits what one can send it.
Also have a look at the following Windows GDI (if that's what's being used) parameter:
DC_ENUMRESOLUTIONS (https://msdn.microsoft.com/en-us/library/windows/desktop/dd183552%28v=vs.85%29.aspx)
Retrieves a list of the resolutions supported by the printer. The pOutput buffer receives an array of LONG values. For each supported resolution, the array contains a pair of LONG values that specify the x and y dimensions of the resolution, in dots per inch. The return value indicates the number of supported resolutions. If pOutput is NULL, the return value indicates the number of supported resolutions.
2. There is no secret component within all the OSes that mysteriously re-samples raster data as it passes from application to printer driver. Therefore, any re-sampling occurs in the application (not likely) or in the driver (denied by Epson)
In the Mac OS there is functionality that is used to do the resampling and the printer driver does the dithering and weaving, in Windows OS it is probably handled by the printer driver, which may call specific DLLs we don't know. What we do know, e.g. from watching the aliasing artifacts, is that (low quality) resampling takes place.
3. The Epson driver allows only certain options to be set by the application directly. Output resolution is generally not one of them (mainly because it interacts with the media type selection). Neither is color handling. It expects the user to set these in the printer settings front end to the driver or will pull them from the default settings (at least on Windows).
The various settings can be sent to the driver by applications. Qimage has been doing that for more than a decade, and if that requires indirectly modifying the media type (because there is no direct input possible) to trigger a certain functionality, then that's how it is done. Not really rocket science.
4. If it was something as simple and obvious as the Epson driver requiring specific input resolutions, that would have been discovered about 30 minutes after the original dither algorithm appeared in 1994 in the original Stylus Color printer.
And it has, and print resolution has been used since. If some applications do not utilize direct influence, but rather rely on default printer behavior (e.g. letting the driver resample to a few fixed, native, resolutions, based on other settings in the printer driver), then that's their choice. More advanced applications use their own (high quality) resampling, plus optionally output sharpening, and send that to the driver that doesn't need to resample anymore.
Cheers,
Bart
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I do not doubt that the Epson printer responds to the Enumerate Resolutions function. I no longer have development environments, nor the driver development kit installed on my machines so I can't verify for myself or report here what response the printer gives. What I do know is that the response is to provide the application with the available resolutions as choices to the user. (I might have to reload some of this stuff to actually monitor/capture the data just to see what is going on. If I do, I will post findings).
I loaded Qimage to see how it uses this data and what it gets. Attached are images with the Epson 3880 and 2400. For the 3880 Qimaged offered resolution choices of 90, 180, 240 and 360. For the 2400 it offered resolutions of 180, 240, 360 and 720. I assume based on what I see in the print dialog that Qimage itself will re-sample to this resolution, though re sampling is not necessary. The surprises here to me are on the 3880 with inclusion of 90 and the max of 360.
And Jeff, yes, I generally send size at 360ppi and sometimes 720ppi if I have that type of density at the size I'm printing. Both Photoshop and ACR are set to a default of 360ppi.
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I loaded Qimage to see how it uses this data and what it gets. Attached are images with the Epson 3880 and 2400. For the 3880 Qimaged offered resolution choices of 90, 180, 240 and 360. For the 2400 it offered resolutions of 180, 240, 360 and 720. I assume based on what I see in the print dialog that Qimage itself will re-sample to this resolution, though re sampling is not necessary. The surprises here to me are on the 3880 with inclusion of 90 and the max of 360.
Those are possible settings for faster output, because less resampling will have to be done by Qimage. That can be useful for poorly written printer drivers that choke on the number of mega/giga pixels it gets sent after interpolation, and huge billboard output doesn't need such high resolution at all, so one might as well speed up the preprocessing.
The (for this discussion) relevant number is the feedback as reported at the top right-hand side of the Qimage window (see attachment for one of the printers I have currently attached). The values will vary with the settings of the printer driver, e.g. output medium.
Cheers,
Bart
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Doesn't the 2400 have 5760 x 1440DPI, and the 3880 2.880 x 1.440DPI as max resolution? And that is why the max of 720 vs 360 in the options?
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Those are possible settings for faster output, because less resampling will have to be done by Qimage. That can be useful for poorly written printer drivers that choke on the number of mega/giga pixels it gets sent after interpolation, and huge billboard output doesn't need such high resolution at all, so one might as well speed up the preprocessing.
The (for this discussion) relevant number is the feedback as reported at the top right-hand side of the Qimage window (see attachment for one of the printers I have currently attached). The values will vary with the settings of the printer driver, e.g. output medium.
Cheers,
Bart
Oh, I see now. Went into 3880 printer setup through Qimage and selected EEF and Highest resolution and finest detail. Got different max and low settings. Actually interesting. Setting the printer to the highest quality of 2880x1440 w/ Finest Detail check and EEF as the media, means the printer will use the a 2880x1440 dither pattern option and yet Qimage will resample to one of 4 different resolutions 180, 240, 360 and 720 while the printer uses it's finest capabilities. Hmm.
Now I really want to see what gets returned to an DC_ENUMRESOLUTIONS because I can't believe the printer would return 90 as an option.
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Doesn't the 2400 have 5760 x 1440DPI, and the 3880 2.880 x 1.440DPI as max resolution? And that is why the max of 720 vs 360 in the options?
Yes, the R2400 has those available resolution. But again, those are not what gets printed, but what is available to get printed. The dither pattern can be calculated using a 5770x1440 matrix.
As Bart pointed out, Qimage does not set the printer resolution. You have to go into the printer driver setup dialog to do that, just like in Photoshop. What it appears you are setting in Qimage is the resolution of the data sent to the printer driver.
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As Bart pointed out, Qimage does not set the printer resolution. You have to go into the printer driver setup dialog to do that, just like in Photoshop. What it appears you are setting in Qimage is the resolution of the data sent to the printer driver.
Correct, the PPI is set as a result of a combination of printer driver choices, and the DPI (dots!) settings are for the dither pattern. Qimage just reads the PPIs that are expected, and does a higher quality resampling than the printer driver offers, output sharpen that at the native printer resolution, before sending that to the printer driver for dithering.
Cheers,
Bart
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Doesn't the 2400 have 5760 x 1440DPI, and the 3880 2.880 x 1.440DPI as max resolution? And that is why the max of 720 vs 360 in the options?
In a way, yes. The dithering pattern is used to produce intermediate ink colors and make the pixels and subsequent printhead passes weave into eachother without abrupt pixel changes. The DPI (dots for dithering) settings are somewhat related to the PPI (pixel resolution) settings. It doesn't make much sense to dither a coarse resolution like 360 PPI with 5760x1440 dots unless one has a limited number of ink colors, it's a bit overkill for the production of intermediate ink colors if the pixel resolution is already high.
Cheers,
Bart
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I do not doubt that the Epson printer responds to the Enumerate Resolutions function. I no longer have development environments, nor the driver development kit installed on my machines so I can't verify for myself or report here what response the printer gives. What I do know is that the response is to provide the application with the available resolutions as choices to the user. (I might have to reload some of this stuff to actually monitor/capture the data just to see what is going on. If I do, I will post findings).
I loaded Qimage to see how it uses this data and what it gets. Attached are images with the Epson 3880 and 2400. For the 3880 Qimaged offered resolution choices of 90, 180, 240 and 360. For the 2400 it offered resolutions of 180, 240, 360 and 720. I assume based on what I see in the print dialog that Qimage itself will re-sample to this resolution, though re sampling is not necessary. The surprises here to me are on the 3880 with inclusion of 90 and the max of 360.
If you keep Qimage's extrapolation set at MAX it will pick the highest input resolution requested by the driver. Any setting below MAX will send less data to the driver but the general assumption is that the driver/OS? does the extra resampling to the requested input resolution then. Whether a lower setting in Qimage speeds up the pre-print processing is dubious, the anti-aliasing algorithm in Qimage may take more time than the upsampling algorithm does, in my experience. A recall print run from the log file will set both Qimage's extrapolation settings (MAX and algorithm type) and the driver print quality settings like they were when the original job was run. So in that case Qimage takes more control of the driver.
Met vriendelijke groet, Ernst
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
December 2014 update, 700+ inkjet media white spectral plots
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In a way, yes. The dithering pattern is used to produce intermediate ink colors and make the pixels and subsequent printhead passes weave into eachother without abrupt pixel changes. The DPI (dots for dithering) settings are somewhat related to the PPI (pixel resolution) settings. It doesn't make much sense to dither a coarse resolution like 360 PPI with 5760x1440 dots unless one has a limited number of ink colors, it's a bit overkill for the production of intermediate ink colors if the pixel resolution is already high.
Cheers,
Bart
I would argue with your characterization of 360ppi as coarse. In continuous tone terms that is actually very good. In dithered terms, it is still very good and almost indistinguishable from 720ppi in real world application. The vast majority of people would be unlikely to identify which was which between prints made from the identical input file: one at 360ppi and the other up sampled to 720ppi in a blind test.
[Added]
As an input resolution in pixels per inch, 360 is very good since it is continuous tone. According to Kodak, for example a 35mm film frame had about 3600 x 2400 pixels or real resolution available or at 360ppi 10"x6.67". I think we are getting spoiled! Now if you were talking about a 360x360 per inch dithering pattern using only 8 colors then, yeah 360 would be fairly coarse. Beyond about 300ppi we are getting into an area similar to $100 worth of monster cable versus $5 worth of 18 gauge zip cord: While some people might actually hear a difference, they can't identify it.
With respect to printing at 5760 for dithering, it is important to always keep in mind that the printer will not lay down 5760 dots, but will have available to it twice as many potential dot locations in that linear direction than printing at 2880. Which is why Epson has never been a big horn blower over the increased resolutions of some of these printers. When pressed, they will flat out tell you that you won't see a difference, except under specific unique circumstance that they won't divulge, between 2880 and 5760. The other complicating factor is droplet spread and ink load properties of the media which is why selection the media type influences the resolutions available. This is why they do tout EEF. It takes a rather high ink load for a gloss paper in combination with the smaller droplet spread that characterizes gloss papers.