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Author Topic: Printing at 300dpi, 360dpi or what  (Read 38791 times)

Eric Myrvaagnes

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Re: Printing at 300dpi, 360dpi or what
« Reply #20 on: October 13, 2011, 11:43:32 pm »

The printing workflows is, in my opinion (which of course, I'm biased about) superior to Photoshop.
Having done quite a bit of printing now from both Photoshop and Lightroom, I emphatically agree. And my only connection with either Adobe or Pixel Genius is that I am a happy customer of both.

Eric
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Geraldo Garcia

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Re: Printing at 300dpi, 360dpi or what
« Reply #21 on: October 14, 2011, 02:32:49 am »

Hello,

I must confess that I was still a bit skeptical about the advantages to up-sample to 300 or 600ppi (I use a HP Z3200) before printing, but reading Jeff and Ernst insisting (once again) that LR 3.x and Qimage algorithms are optimised to work that way I decided to give it a try. I own both softwares but usually print from Photoshop (or used to).

Today two clients cancelled their appointments giving me about to 3 hours free to play, so I carefully selected an image that was sharp, had various different textures and some low and high contrast areas. The image would be about 242ppi at 24" width. First I processed the image as I usually do and printed it 6 times on Cansosn Photo Satin Premium RC 270g paper on the following order:

1) Printed from PS without up-sampling at 242ppi
2) Printed from LR3.5 without up-sampling at 242ppi with "standard glossy" print sharpening
3) Printed from LR3.5 up-sampling to 300ppi with "standard glossy" print sharpening
4) Printed from LR3.5 up-sampling to 600ppi with "standard glossy" print sharpening, printer set to "maximum quality" (I know I should do that only if the image was originally above 300ppi, but I did just for fun)
5) Printed from Qimage up-sampling to 300ppi with "standard" print sharpening, "fusion" interpolation
6) Printed from Qimage up-sampling to 600ppi with "standard" print sharpening, "fusion" interpolation, printer set to "maximum quality" (again just for fun)

Then I numbered the prints and spent about an hour looking at them side by side on the light booth. I also showed them to my wife (and business parter) and some other photographers. Everyone agreed that (1), (2) and (4) were the worse in therms of sharpness and detail, proving that Jeff Schewe is right (as usual). But, curiously, there was no consensus about images (3), (5) and (6) and honestly I would approve any of those if presented separately.  Image (6) was the anomaly, would not dare to say it is sharper and has more than (3) and (5), but it for sure is no worse.

I will try to test some other image tomorrow, this time an image that is above 300ppi.
Many thanks Jeff and Ernst, as I am now convinced!

Best regards.
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Ernst Dinkla

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Re: Printing at 300dpi, 360dpi or what
« Reply #22 on: October 14, 2011, 04:10:44 am »


Personally, for ink jet printing I would NEVER downsample. Why waste your resolution?


Enough textured matte art media around that does not give the image quality to make that 60 PPI + sharpening step visible. With several drivers the highest quality setting is not even available for media below that quality. There are good arguments to keep for example droplet size bigger and by that print resolution lower on media that is not at the highest quality standards. Dotgain of smaller droplets is higher than dotgain of small droplets, addressing larger droplets is easier than addressing smaller droplets, Dmax on matte media often is best with larger droplets. An Epson running at 720 PPI or 1440 PPI uses only the minimum droplets, excellent for very even, high quality surfaces but not always for rougher textures. In some cases users have to run at the highest quality and slowest printing speeds as the printer is not consistent in its output; more banding issues at the faster settings. This has nothing to do with the better quality of the transferred printer data but is a separate issue.

Then there is a practical issue: an image file that does not go through the upsampling and sharpening routines of for example Qimage gives a much lower amount of printer data to transfer. It is the opposite of lossy JPEG compression of images when you improve the image data with Q's routines; more information has to be transferred to the printer as there is more "quality" created. Sending 720 PPI data to the driver is already a lot more than sending 360 PPI data, better upsampling + sharpening routines expand that even more. With larger prints that can be problematic with memory and in any case both processing speed and printing speed suffer considerably when you always go for the 720 PPI + best upsampling and sharpening route. With 16 bit printer data that is again doubled. If the print quality gain is not visible or not worth it I would use 360 PPI + best resampling and sharpening. One of the advantages of the HP and Canon wide format printers is that the two rendering resolution are less demanding for printer data processing, choices are 300 and 600 PPI, the desktop models like the B9180 however have the 1200 PPI rendering print quality setting but produce smaller print sizes. Older Z3100 firmware had a 1200 PPI rendering printer quality setting while the newer Z3200 did not go higher than 600 PPI rendering resolution, I could not see a quality difference on detail between both. HP probably neither as the the latest Z3100 firmware no longer gives that 1200 PPI rendering choice. They could have improved the dithering/weaving in the same upgrade but the driver asks for 600 PPI input now.

I am not against that rule of upsampling whenever possible to the first rendering resolution above the available image resolution at print size but there is a nuance to that rule, as there is always a nuance. I have often used that upsampling rule with the notion that drivers ask for specific rendering resolutions, Qimage makes the user very aware of the parameters in the process. It also has the flexibility to create an optimal alternative: adaptable anti-aliased downsampling + smart print sharpening and the driver not interfering afterwards.


met vriendelijke groeten, Ernst

New: Spectral plots of +250 inkjet papers:

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
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narikin

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Re: Printing at 300dpi, 360dpi or what
« Reply #23 on: October 15, 2011, 11:36:42 am »

I have to print many huge images from Phase One P65+ files: These are large prints - over 75" long, so viewing will be relative, but results so far are very decent.

The print size was chosen to be 120ppi native - an exact 1/3 of 360dpi that the Epson requires. So we are not dealing with random uprez in awkward fractions here. But are people suggesting I should uprez it to 180dpi, or 360dpi (!) from RAW in C1 or from TIFF in PS, then sharpen, then print?  It's hard to imagine this will make a lot of difference, when I have an exact multiple already, but opinion here seems to say it might.

The other option is QImage, which I know and like, allowing that do the work, BUT the images require special local area sharpening, so I can't use QI own sharpening procedures for that, sadly.

ps: I can't use Lightroom, as its Phase One profiles are not that good.


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Bart_van_der_Wolf

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Re: Printing at 300dpi, 360dpi or what
« Reply #24 on: October 15, 2011, 12:51:29 pm »

The print size was chosen to be 120ppi native - an exact 1/3 of 360dpi that the Epson requires. So we are not dealing with random uprez in awkward fractions here. But are people suggesting I should uprez it to 180dpi, or 360dpi (!) from RAW in C1 or from TIFF in PS, then sharpen, then print?  It's hard to imagine this will make a lot of difference, when I have an exact multiple already, but opinion here seems to say it might.


While it can at times be beneficial to resample in integer fractional sizes compared to the printer's native resolution, I've seen no solid evidence that it really matters (it won't hurt either). It would matter if the printer driver has built in optimizations for certain fixed multiple interpolation/decimation ratios. My main hesitation in recommending e.g. 120 or 180 PPI is with the unknown quality of the interpolation to whatever the printer requires.

Quote
The other option is QImage, which I know and like, allowing that do the work, BUT the images require special local area sharpening, so I can't use QI own sharpening procedures for that, sadly.

You can do that, or perhaps even better. Qimage allows to File|Print To|File (e.g. in the output colorspace if you like). Then edit the print-file by using whatever latest invention you may have available for sharpening. In addition, you can have Qimage automatically interpolate to whatever resolution the printer driver feedback reports as optimal. Sharpening at that output resolution is also optimal, and there is no need to guess if/which integer fractions offer a benefit or not.

Cheers,
Bart
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narikin

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Re: Printing at 300dpi, 360dpi or what
« Reply #25 on: October 15, 2011, 01:24:51 pm »

In addition, you can have Qimage automatically interpolate to whatever resolution the printer driver feedback reports as optimal. Sharpening at that output resolution is also optimal, and there is no need to guess if/which integer fractions offer a benefit or not.
Cheers,
Bart

thanks Bart. very useful. I understand all of this, except the bit about 'printer driver feedback' - where does the printer driver tell you what is wants? - or are you referring to the feedback on these pages telling us to work at 360dpi for Epsons.

I guess I should test at 720dpi output on the Epson too at this size. might be asking less from the interpolation, and end with different results.
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Bart_van_der_Wolf

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Re: Printing at 300dpi, 360dpi or what
« Reply #26 on: October 15, 2011, 03:30:58 pm »

thanks Bart. very useful. I understand all of this, except the bit about 'printer driver feedback' - where does the printer driver tell you what is wants? - or are you referring to the feedback on these pages telling us to work at 360dpi for Epsons.

Qimage takes away all the quesswork because it interrogates the printer driver about which PPI it expects based on the driver settings (e.g. paper type and ink choices). The printer driver responds with the optimal PPI (shown at the top right above the layout preview page) and Qimage automatically resamples the images to exactly that while observing the layout preferences, border widths, etc. It uses a superior resampling algorithm compared to the printer driver's to do the resampling, and can finally Smart sharpen based on the amount of interpolation from the original file dimensions.

If the resulting output size is such that the best quality would result in excessive printing times or spoolfiles, then one can instruct Qimage in the layout properties to drop the output resolution for Posters from Max, to High, or Medium, thus forcing a lower PPI resampling. You can also let Qimage cut up the images in multiple edge aligned posters of e.g. mounting panel size if the full print is larger than the available paper.

All of the print output can be directed at files (e.g. off-site printing or manual sharpening, retouching, reprinting, multiple printers, etc.) or directly at the printer.
 
Quote
I guess I should test at 720dpi output on the Epson too at this size. might be asking less from the interpolation, and end with different results.

Except for larger (spool) files, there may well be additional resolution to be had if not by the interpolation method used (which attempts to straighten jagged/stairstepped input and gives a smooth organic look to gradients and small detail). If 720 PPI output is warranted, then the printer driver should be set to finest detail, otherwise it will suggest 360 PPI maximum to Qimage.

Cheers,
Bart
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narikin

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Re: Printing at 300dpi, 360dpi or what
« Reply #27 on: October 15, 2011, 04:14:26 pm »

Except for larger (spool) files, there may well be additional resolution to be had if not by the interpolation method used (which attempts to straighten jagged/stairstepped input and gives a smooth organic look to gradients and small detail). If 720 PPI output is warranted, then the printer driver should be set to finest detail, otherwise it will suggest 360 PPI maximum to Qimage.
Bart

Thanks Again Bart. very useful stuff. will re-familiarize myself with Qimage and try these.

One bit of confusion - my fault- is I meant setting the Epson printer to 720dpi, (rather than 1440 or 2880) for such very large prints, not the image ppi to 720.  I'd imagine the printer asks less of Qimage, and so less interpolation is needed.
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Bart_van_der_Wolf

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Re: Printing at 300dpi, 360dpi or what
« Reply #28 on: October 15, 2011, 05:38:03 pm »

Thanks Again Bart. very useful stuff. will re-familiarize myself with Qimage and try these.

One bit of confusion - my fault- is I meant setting the Epson printer to 720dpi, (rather than 1440 or 2880) for such very large prints, not the image ppi to 720.  I'd imagine the printer asks less of Qimage, and so less interpolation is needed.

The image PPI simply follows from the image pixels divided by the required output size. The number of required output pixels per unit length are determined by the printer driver settings. Qimage makes up for the difference by resampling to the exact number of pixels required, and do sharpening at the final output size. No intermediate files are required (everything happens in the background), although one can produce files for specific requirements.

If the output size results in only few original image pixels per output dimension (shown in the Queue list as image PPI), then it may not be necessary to use the full printer resolution capability. It won't technically hurt, but it may take a long time to print with increasingly little quality gain, in which case the Qimage output settings for resolution in the job properties can be relaxed a bit (Max->High->Medium). It's easier to do than to explain.

Cheers,
Bart
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deanwork

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Re: Printing at 300dpi, 360dpi or what
« Reply #29 on: October 15, 2011, 08:55:45 pm »

Has Epson improved their file resampling algorithms in the latest 9900 and 9880 driver models? I'm also wondering if the IPF8300 plug-in has major changes over Canon's previous model when it comes to pixel optimization and enlargement of files sent to it at smaller than ideal sizes.

j
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hjulenissen

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Re: Printing at 300dpi, 360dpi or what
« Reply #30 on: October 15, 2011, 09:08:06 pm »

While it can at times be beneficial to resample in integer fractional sizes compared to the printer's native resolution, I've seen no solid evidence that it really matters (it won't hurt either). It would matter if the printer driver has built in optimizations for certain fixed multiple interpolation/decimation ratios. My main hesitation in recommending e.g. 120 or 180 PPI is with the unknown quality of the interpolation to whatever the printer requires.
All image scaling introduce aliasing/imaging to varying degree. If the scaling factor is a division of two small numbers, the aliasing artifacts tends to be "consistent" for periodic input, and therefore less annoying.

-h
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Schewe

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Re: Printing at 300dpi, 360dpi or what
« Reply #31 on: October 15, 2011, 10:02:00 pm »

Has Epson improved their file resampling algorithms in the latest 9900 and 9880 driver models?

Resampling? Again I really don't think the driver resamples the image data....I think the print pipeline does. But if you are asking about the error diffusion dither of the x900 & x890 (not the x880 series) then yes, the dither is much finer.
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Ernst Dinkla

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Re: Printing at 300dpi, 360dpi or what
« Reply #32 on: October 16, 2011, 07:45:33 am »


If the resulting output size is such that the best quality would result in excessive printing times or spoolfiles, then one can instruct Qimage in the layout properties to drop the output resolution for Posters from Max, to High, or Medium, thus forcing a lower PPI resampling. You can also let Qimage cut up the images in multiple edge aligned posters of e.g. mounting panel size if the full print is larger than the available paper.

Cheers,
Bart

If the Max setting of resampling is not used in Qimage but High or Normal then the driver will do the last step of resampling to the rendering resolution in PPI of the print quality (dot resolution in dpi, more or less weaving strokes, etc) selected in the driver, for example from the 300 PPI delivered by Qimage to the 600 PPI asked for by the driver. That is what I understand of the Qimage choices on interpolation quality. At least that is obvious in the example mentioned as Qimage shows that lower output resolution next to choice while the higher requested rendering resolution is shown above the preview window.


met vriendelijke groeten, Ernst

Try: http://groups.yahoo.com/group/Wide_Inkjet_Printers/
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Ernst Dinkla

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Re: Printing at 300dpi, 360dpi or what
« Reply #33 on: October 16, 2011, 08:01:36 am »

Resampling? Again I really don't think the driver resamples the image data....I think the print pipeline does.

Somewhere between the application and the inkjet heads a resampling happens, up or down and to two or three specific rendering resolutions. The aliasing tests have shown that behaviour as discussed in the older thread. Possibly more number crunching is done internally on wide format printers than happens on desktop models in view of what is demanded and in view of printer costs. Where it happens after the application sends the data is not important I think, that specific rendering resolutions exist is however good to know.


met vriendelijke groeten, Ernst

New; 250+ Spectral plots soon extended with the Canon US catalog:

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm







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Bart_van_der_Wolf

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Re: Printing at 300dpi, 360dpi or what
« Reply #34 on: October 16, 2011, 08:50:49 am »

All image scaling introduce aliasing/imaging to varying degree. If the scaling factor is a division of two small numbers, the aliasing artifacts tends to be "consistent" for periodic input, and therefore less annoying.

Most real life images have a variety of detail and therefore offer various spatial frequencies. There's probably no frequency that doesn't align with the sampling period at some point and at the same moment most others don't align. Also, as for this thread's topic, producing large output usually means we're dealing with undersampled (for the output size) detail, thus forcing us to interpolate to get more pixels. That poses different challenges (filling in the 'gaps' with credible detail) than downsampling does.

Now, let's consider the seemingly simple case of 2x upsampling, say from 180 PPI input to 360 PPI printer requirement. That would mean that for each 2 pixels 1 pixel has to be interpolated exactly in between the two, and the two original pixels are unchanged. Sounds like a simple enough thing, fit for a printer driver which is built for speed.

Well, that may be an underestimation of the complexity we're faced with. Let me remind you that the original pixels, coming from an MF camera without proper AA-filter, are aliased to begin with (e.g. stairstepped edges and lines, especially when sharpened at native resolution, prior to upsampling).

We will possibly be better of by not leaving the original pixel values unchanged, but by prefiltering them in addition to adding interpolated pixels. What's more, the interpolation should ideally be done in linear gamma space, but we have no idea what gamma adjustments have taken place to create the image file we're sending to the printer driver (which therefore probably assumes nothing), and that's on top of the gamma 1/2.2 precompensation for display.

Cheers,
Bart
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Bart_van_der_Wolf

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Re: Printing at 300dpi, 360dpi or what
« Reply #35 on: October 16, 2011, 08:58:37 am »

If the Max setting of resampling is not used in Qimage but High or Normal then the driver will do the last step of resampling to the rendering resolution in PPI of the print quality (dot resolution in dpi, more or less weaving strokes, etc) selected in the driver, for example from the 300 PPI delivered by Qimage to the 600 PPI asked for by the driver. That is what I understand of the Qimage choices on interpolation quality. At least that is obvious in the example mentioned as Qimage shows that lower output resolution next to choice while the higher requested rendering resolution is shown above the preview window.

Hi Ernst,

Yes, that what I understood as well, it lowers the quality/resolution of data sent to the printerdriver to save time (e.g. over a network) or to prevent spool memory issues. That doesn't mean that the driver doesn't still resample on it's own, if set to a normal or higher output resolution.

Cheers,
Bart
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datro

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Re: Printing at 300dpi, 360dpi or what
« Reply #36 on: October 16, 2011, 11:04:30 am »

I always prefer printing from Lightroom vs Photoshop for a variety of reasons–first off, Lightroom only cares about pixel dimensions, not size and resolution. So, if you need a small print, simply set the dimensions of the cell size and the resolution auto-flows...big print where you need less? again, it auto-flows. So you don't need to spawn off multiple files just to print different sizes.

Lightroom has an optimized upsampling that is image adaptive. If you upsample, LR interpolates between Bicubic and Bicubic Smoother depending on the size.

The last phase is output sharpening...which I had an involvement in since Adobe worked with PixelGenius to bring output sharpening to Lightroom.

The printing workflows is, in my opinion (which of course, I'm biased about) superior to Photoshop.

Jeff, I do all my editing in Photoshop on drum-scanned large format B&W negatives and have always printed to my Epson 7900 from Photoshop to maintain a workflow that is reasonably straightforward.  I'm trying to understand if there would be any significant value in changing my workflow to take my edited images and move them into LR for printing.  I guess I'll have to run some tests myself, but you mention that LR has an "adaptive" upsampling that interpolates between Bicubic and Bicubic Smoother.  If I were to choose to stick with PS for printing, what guidelines can you give for when to choose Bicubic vs. Bicubic Smoother when upsampling to the target 360 or 720?

Dave
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Bart_van_der_Wolf

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Re: Printing at 300dpi, 360dpi or what
« Reply #37 on: October 16, 2011, 12:00:57 pm »

If I were to choose to stick with PS for printing, what guidelines can you give for when to choose Bicubic vs. Bicubic Smoother when upsampling to the target 360 or 720?

For upsampling in Photoshop, use Bicubic Smoother (which produces the least artifacts), and then do the sharpening (e.g. Smart sharpening, More Accurate mode, try Lens blur first) at the final output resolution. You can push the Smart sharpening amount further in the absence of artifacts, and the radius would be your normal radius (0.7?) multiplied by the upsampling factor, for starters.

The result can be every bit as good as from Lightroom.

Cheers,
Bart
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Jsostar

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Re: Printing at 300dpi, 360dpi or what
« Reply #38 on: October 16, 2011, 05:59:31 pm »

I understand the rule for an Epson printer that an image at or under 360 ppi,  resample the picture to 360 ppi and then print.

General guide lines for up-sizing in Photoshop using bicubic smoother.

My question is how much can an image be up sampled before image quality will be effected?

Example:  My original image size is 10.4 x 15.6 inches at 360 ppi.  I print my large images at 20 x 30 inches.  In this example I would have to double the width and height to stay at the same resolution (quadrupling the image size).

What I have been doing is resizing my image to 15.6 x 23.4 inches at 240 ppi and up sampling to 20 x 30 inches at 240 ppi and then printing.   This method does not require up sampling by a large amount.

I do my output sharpening after resizing the print.

I do plan on printing an image both ways and testing.

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Ernst Dinkla

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Re: Printing at 300dpi, 360dpi or what
« Reply #39 on: October 17, 2011, 03:14:59 am »


My question is how much can an image be up sampled before image quality will be effected?



Pixel qualities differ, image content differs, media print qualities differ, print viewing distances can be taken into account, etc etc.  In the end some proof strips and your eyes become the decisive factors. At some point you have to find a compromise between upsampling/sharpening artefacts and image softening, the best upsampling routines stretch that a bit. There are no strict rules in my opinion. The amount of upsampling can be better judged by setting the image size in Photoshop at the intended print size (without resampling), then check the PPI number there and compute the upsampling ratio with the knowledge that the printer/driver will ask for either 360 or 720 PPI.


met vriendelijke groeten, Ernst

New; 250+ Spectral plots soon extended with the Canon US catalog:

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm


« Last Edit: October 17, 2011, 11:57:24 am by Ernst Dinkla »
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