Luminous Landscape Forum
Raw & Post Processing, Printing => Printing: Printers, Papers and Inks => Topic started by: abaazov on February 05, 2006, 10:49:20 am
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from what i understand, there are many ways to resize an image. i was wondering what would be the best way to make an image smaller. for example, i have an image that is 12x18 with a ppi resolution of 240. i want to print it at 11x17. i can increase the ppi to around 265, and that will give me the print size i want. is that better, worse, or the same as resampling the image to fit into 11x17?
thanks....
amnon
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You'll find as many answers to this as their are photographers.
My rule of thumb, is that when I resize for printing I let the PPI go as low as 240 without worrying about it.
Below 240 I will use Photoshop's Bicubic Smoother to set the output to 240 at whatever size I want.
It used to be that some people would upres in small increments, but this was rendered unnecessary when the Smoother function was introduced.
Some people believe (or have found though their own testing) that products designed for upressing do a better job that Bicubic Smoother. The last time I did my own tests (a couple of years ago) I didn't find a single one that did visibly a better job on prints at normal viewing distances).
Michael
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thanks michael
amnon
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What's nice about Qimage (PC only) is that you don't have to worry about resizing at all. It's uprezzing technology is at least as good as PS and it optimizes dpi on the fly.
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I have used Genuine Fractals for resizing and love the results. It provides the most direct approach for me.
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Amnon,
I like Michael's advice on this. I do likewise.
That much said, there are a few additional comments to address the questions you asked.
Firstly, in the case you asked about, you are downsizing, not up-sizing. If you wish to have a specific image resolution (PPI) - necessary for some things, but not others - when you are downsizing, in the Photoshop Image Size dialog box you would select "Bi-cubic Sharper" rather than "Bicubic Smoother". The former is for downsizing and the latter for up-sizing.
Like Michael, normally when I change the linear dimensions of an image I leave "Resample Image" UNCHECKED, I change the linear dimensions to what I want and let the PPI resolution take care of itself, as long as the PPI doesn't sink much below 240 when I am up-sizing. This is because it is best for image quality to avoid resampling as much as possible and 240 produces a very acceptable large format print (at least on Epson 4000/4800 printers where I know from personal experience).
Now, since you are REDUCING the linear dimensions in the example you asked about, when you leave "Resample Image" unchecked and change one of the linear dimensions (with "constrain proportions" on), the PPI will increase, which is fine. If you reach a point where PPI increases beyond 480, you may wish to resample down to this maximum value, because sending more than 480 PPI to the printer really achieves nothing - you are hyper-rich in resolution.
In the example you gave, moving from 240 to 265 by just changing the linear dimensions with "Resample Image" UNchecked is theoretically the best of all worlds because you are getting more resolution without any quality degradation from the resampling process - though I agree with Michael that Photoshop's new resampling algorythms are so good that within a reasonable range you won't really notice the difference.
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Scott Kelby adds an interesting wrinkle to the process of upwards resizing in The Photoshop CS2 Book (p.109). He suggests using Bicubic Sharper gives better results.
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I've seen that too, but I haven't bothered to test it because I re-res so seldomly and get great results using Adobe's intended tools when I do; that said, Scott most likely has tested it, so he may well be right, but I wonder in what circumstances the difference would really become noticeable.
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Another method I have seen advocated is to upsize to about 5% larger using Bicubic smoother and then downsize to the required size using Bicubic sharper.
This was stated to be almost as good as using fractuals in Qimage.
I have used this method to enlarge a 6.1 mega pixel camera image to A1 size with very acceptable results.
Peter
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I guess I'm the odd one out; I prefer bicubic smoother to resize to smaller images, but that's usually for web usage.
Maybe I should try using sharper for a while to see if I'm more pleased with the results now than I used to be.
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what about resizing in camera raw? is that a good/bad idea?
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In theory I agree with the " don't resample" advice. In practice when printing for clients, I ask for files to be sized at 360ppi. This avoids having to deal with resolutions way outside acceptable limits.
There is a school of thought that suggests that if the native resolution of the printer is , say 720 ppi, as I believe the Epson 800 series is, then resolution of file should be 180, 360 or 720. Maybe the printer doesn't have to think too much then! With 180 below general acceptability and no advantage of 720, then 360 remains. I have not noticed , nor has any comments, regarding loss of acuity by resampling to 360ppi. Knowing how to sharpen properly seems much more important and I always ask for files that have no sharpening at size applied so that I can do it. I think there could be a book written on sharpening. Further I sharpen on a seperate layer on a duplicate of the original and would have a duplicate for each size to be printed. Sharpening would most likely be different for different sizes.
I use the PS Bicubic options for resizing. For large shifts I still move 10% at a time, which may be just habit, but a number of respected printers still advocate this approach even with the recent algorithms.
As an aside , I am at the moment experimenting with printing at 720 ppi a vector file from Illustrator that I have converted in Photoshop. I realize rasterisation in a RIP is the preferred approach, but I am awaiting some results of RIP comparisons before lashing out on one for the 9800.
The vector file requires considerable upressing and there are small jaggies at 100%.I would welcome comments from anyone with experience in dealing with this sort of file.
Cheers
Brian
Pharos Editions
www.pharoseditions.com.au
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There is a school of thought that suggests that if the native resolution of the printer is , say 720 ppi, as I believe the Epson 800 series is, then resolution of file should be 180, 360 or 720.
My understanding is that it's 360 for the 48/78/9800. Selecting "Finest Details" bumps it to 720. The smaller desktop models are all supposed to be 720.
I also go with 360 (exactly). If the file size is close to what's required, I up/downsample with vanilla Bicubic. If the change is somewhat larger, I use Bicubic Smoother (upsample) and Bicubic Sharper (downsample). In all cases, immediately prior to printing I apply fixed output sharpening optimized for 360 (using an Action based on TLR's scripts - http://www.thelightsrightstudio.com/) (http://www.thelightsrightstudio.com/)). I think the differences with a range of resolutions are however likely to be subtle, but giving the driver exactly 360 is the optimum ... in theory. If your files sizes are always limited you may want to consider a similar workflow based around 240 (exactly).
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I did some actual experiments with my Epson awhile back, and have reiterated the results here a few times since then, but it sounds like it's time to repeat them for newcomers:
There is no discernable difference between 240 ppi and 360 ppi. 180 ppi is slightly worse (but you have to look very closely to see the difference). Sending it to the printer at the native resolution without resizing (in my particular experiment, about 215 ppi) was noticeably worse than any of the preceding cases, even than the 180 ppi case. This indicates that the printer's internal interpolation routine is worse than Photoshop's.
Calypso Imaging suggests that you can start with images down to about 150 ppi and still have them come out "good", though not excellent. For excellent, you need more like 240 ppi.
Lisa
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I very seldomly resample images. I change the linear dimensions and let the PPI change accordingly (meaning all the original pixels remain, only their size changes to accommodate more or fewer of them per inch of output), as long they remain within a range of 180 to 480. Quality is usually acceptable at 180 or even a bit below. Between 240 and 480 you have to look very hard and use some imagination to discern quality differentials on prints (in my case printed on Epson Enhanced Matte using an Epson 4800 with K3 inks). The integer divisor issue and the printer's so-called "native resolution" issue may be interesting theory, but they are heavily over-rated in terms of their operational signifigance.
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The integer divisor issue and the printer's so-called "native resolution" issue may be interesting theory, but they are heavily over-rated in terms of their operational signifigance.
I did the experiment myself, and, I assure you, the integer divisor issue has a significantly greater effect than the 180 vs. 360 issue.
Lisa
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I am totally with Tim on this one. Resizing for printing is just a pfaff. This is why I used to sometimes use CS2's print with preview controls to fit the image to a particular print size. Lets say I had converted a 1DS MKII raw file with Capture One to an output resolution of 300. This would give print dimensions approximately conforming to about an A3+ sheet of paper. Therefore, CS2 must downsample this file to print onto A4 paper. Not a problem you would think for such an expensive application with all of its sophisticated tools. However, I kept getting aliasing on sharply defined edges and I could just could not understand why. Qimage on the other hand uses sophisticated algorithms to resample images for printing (?Lanczos interpolation). Absolutely perfect prints of any size every time and no need to alter the original converted Tiff. Qimage also does not run out of steam like Photoshop when printing reallly big images. It really is a nice program and excellent value for money. Next best thing to a RIP and at a fraction of the cost.
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With my Canon 1Ds as well, something has to give squeezing all that information into an A4 or letter-size image. I simply don't resample. If I use the full frame and dimension the printed image area to Letter-size paper (just a bit different from the UK's A4) I do a 9*6 inch image and that yields 451.556 PPI. I've tested alternative outputs by cropping the image to provide 360PPI or I've re-rezzed the whole thing to 360 PPI using bicubic sharper. I couldn't see the difference on the prints.
Likewise, an A3 from full frame is 14.5 by 9.65 inches of printed area at 280.276 PPI, and I find it very difficult to detect quality difference whether one prints this at 240, 280 or up-rezzed to 360.
I have had quality problems up-rezzing severe crops to fill an A3 from something as low as 120 PPI starting to 240 target - here one sees some brittleness in the resulting image texture. I'm yet to try QImage, though I keep hearing great things about it. Perhaps testing results depend partly on the nature of the image being tested, the printing environment, how sharp one's eyes are, etc. Likely quite a few variables.
Anyhow, for what it's worth I collaborated with Harald Johnson on resolution settings for scanning film (where the integer divisor debate is also alive and well) and we came to similar conclusions (there is alot of latitude) - this is reported in his Mastering Digital Printing Second Edition pages 83 to 85).
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There is no discernable difference between 240 ppi and 360 ppi.
Try this. Create a new image at 240ppi, white canvas, draw a 300x300 black pixel square and add some text in the middle, say Helvetica 3pt. Create a second image, this time at 360ppi, draw a 450x450 pixel square (same corresponding size) and add the same text, again at 3pt. Print both out on Enhanced Matte (or similar) at 1440dpi unidirectional. Compare. My eyes aren't great these days but I can see a difference both in the weight of box and the resolution of the text. Without a loupe. The same would apply for any micro details in your files ... assuming the information is there in the first place.
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Stephen,
I am sure you will see a discernable difference. What I also urge you to try is leaving your test file at 360ppi and sizing the print job using print with preview in Photoshop and then doing the same with Qimage. I am fairly certain you will be impressed by the difference.
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Stephen,
I am sure you will see a discernable difference. What I also urge you to try is leaving your test file at 360ppi and sizing the print job using print with preview in Photoshop and then doing the same with Qimage. I am fairly certain you will be impressed by the difference.
[a href=\"index.php?act=findpost&pid=58274\"][{POST_SNAPBACK}][/a]
I have a Mac though I did have a brief look at Qimage in Virtual PC. Most of my own prints are downsampled from larger files, and if upsampled (to 24x30) only by about 5%. The only time I use Print with Preview to resize is for quick and nasties :-).
One practical application of the difference between 240ppi and 360ppi is a single pixel border I add to my own images (part of the pre-print Action). I'm after the lightest/thinest border I can get to just hold in the image (sky areas etc).
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Stephen,
Returning to Qimage again, there is a feature which automatically turns on a very thin black border all round the image which I use in exactly the same way.
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Stephen,
Returning to Qimage again, there is a feature which automatically turns on a very thin black border all round the image which I use in exactly the same way.
[a href=\"index.php?act=findpost&pid=58278\"][{POST_SNAPBACK}][/a]
Ack! You mean everybody's doing this? :-).
I'm surprised not to see some photos of North Wales on your site. Some lovely country there.
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Everything printed from Qimage, big or small, is at least 360ppi, isn't it? In fact, sometimes an image that is already 360ppi will be uprezzed to 720ppi by Qimage. Not sure why. Possibly because it's actually 360.1ppi and Qimage only uprezzes.
Maybe there's some adjustment in some preferences option I've missed, but it's never been of much concern to me. A bit of pixel-peeping is fine, but trying to find any meaningful difference between 240 and 360ppi, or even between GF and bicubic in normal size prints that haven't been interpolated by a really huge degree, is pixel-peeping carried to the extreme.
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Everything printed from Qimage, big or small, is at least 360ppi, isn't it? In fact, sometimes an image that is already 360ppi will be uprezzed to 720ppi by Qimage. Not sure why. Possibly because it's actually 360.1ppi and Qimage only uprezzes.[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=58281\")
FYI: [a href=\"http://www.ddisoftware.com/qimage/quality/]QImage ppi handling[/url].
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..........trying to find any meaningful difference between 240 and 360ppi, in normal size prints that haven't been interpolated by a really huge degree, is pixel-peeping carried to the extreme.
[a href=\"index.php?act=findpost&pid=58281\"][{POST_SNAPBACK}][/a]
I don't know what size range you include in "normal", but if normal includes A4 and A3, based on the extensive amount of printing I've done of all kinds of photographs at various resolutions from 180 to 451 on an Epson 4000 and then an Epson 4800, I agree with you. However, it matters whether one is discussing resizing or resampling. For resizing, looking for quality differences accross a range of 240 to 360 or 360 and above is largely unproductive pixel-peeping. However, if one is talking resampling by large amounts from low starting points, methodology and tools matter. In fact, highly-regarded professionals who have tested this stuff extensively - be it for production, educational or software development purposes - generally recommend to avoid resampling unless there is absolutely no choice, and then to minimize it.
I would at the same time add some comment on the question of the Printer driver's "native resolution", because this is not as straightforward a concept as one would like to believe it should be, hence it is simplistic to theorize that converging an image's PPI with the "native resolution" of the printer, or using integer divisors is somehow superior to not doing so.
Based on what I have learned through discussion with professionals who have deep knowledge of these matters, when one talks about an inkjet printer's "native resolution" of say 360, inkjet printers lay down ink dots, not pixels. The print head itself has ink nozzles 1/360th of an inch apart. The 720, 1440, and 2880 numbers are obtained by the stepper motor moving the printhead by those smaller increments and the printer's weaving algorythms. Through processes of dithering that are corporate secrets of the printer manufacturers, pixels get converted into ink dots. Basically, these processes overlay the image pixels on a 360-cell-per-inch grid, and for each cell, calculates how to turn the pixels into dots of ink.
What all this really means is that there is no choice but to simply use one's eyes, look at prints made at various PPI and printer settings on various media - and see within the range of stuff one normally does whether any of this (short of major resampling) makes a serious difference. My own experience mentioned above suggests that it rarely does, so I am back to Ray's point about pixel-peeping.
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QUOTE(nniko @ Feb 15 2006, 11:12 PM)
There is no discernable difference between 240 ppi and 360 ppi.
Try this. Create a new image at 240ppi, white canvas, draw a 300x300 black pixel square and add some text in the middle, say Helvetica 3pt. Create a second image, this time at 360ppi, draw a 450x450 pixel square (same corresponding size) and add the same text, again at 3pt. Print both out on Enhanced Matte (or similar) at 1440dpi unidirectional. Compare. My eyes aren't great these days but I can see a difference both in the weight of box and the resolution of the text. Without a loupe. The same would apply for any micro details in your files ... assuming the information is there in the first place.
My experiments weren't with text and drawn boxes, because that's not what I (and the vast majority of others here) are printing; my experiments were with a typical landscape photo. I'm not surprised that you might see a difference between 240 & 360 when you're looking at printed text, but that's pixel-peeping. For a normal landscape photo, I saw no difference, and that's what matters to me.
I would at the same time add some comment on the question of the Printer driver's "native resolution", because this is not as straightforward a concept as one would like to believe it should be, hence it is simplistic to theorize that converging an image's PPI with the "native resolution" of the printer, or using integer divisors is somehow superior to not doing so.
I never made any claims about any theory behind the "printer native resolution" issue. I don't give a !@#$ about theory, only about results. All I did was report that, in practice, with a typical landscape photo, it *did* make a difference (a quite small one, but more noticeable than the 240/360 issue).
Perhaps we are making mountains out of molehills, arguing about whether something is "small" vs. "none", when, in reality, it's not worth the time worrying about it one way or the other.
Lisa
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I never made any claims about any theory behind the "printer native resolution" issue. I don't give a !@#$ about theory, only about results. All I did was report that, in practice, with a typical landscape photo, it *did* make a difference (a quite small one, but more noticeable than the 240/360 issue).
Perhaps we are making mountains out of molehills, arguing about whether something is "small" vs. "none", when, in reality, it's not worth the time worrying about it one way or the other.
Lisa
[a href=\"index.php?act=findpost&pid=58313\"][{POST_SNAPBACK}][/a]
I wasn't talking theory either - I was talking about the practical realities of how printers work, in order to make two points on which we both seem to be agreed: (i) what matters is what normal photographs look like on paper, and (ii) the quality differences we're talking about here aren't worth the time worrying about.
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Dale,
Thanks for pointing out that article on Qimage. I do remember reading it the first time, just before I gave it a try. I did not give it much notice at the time because Qimage is so cheap, I just was not prepared to give much credence to the claims. However, I am a total convert now and I really think that Photoshop is a poor application to print out of. Not convinced? Let me show you a real-world photograph:
(http://www.pbase.com/drewbie/image/56156923.jpg)
That is the whole image. Now two identically sized A4 prints and a sectional flat-bed scan of each, the first sized in PS CS2 print with preview. Remember, both prints are made from the same uncropped 16-bit Tiff from a 1DS MKII at 300ppi, so plenty of resolution for a good A4 print. Both also made with the same output profile. I could also show you examples from prints at native resolutions (i.e. no adjustment of size to fit the print) and the same sorts of problems are manifest, they just happen to be particularly obvious in this example.
(http://www.pbase.com/drewbie/image/56157007.jpg)
Next sized in Qimage.
(http://www.pbase.com/drewbie/image/56157015.jpg)
Note how the Photoshop print is less sharp and displays very obvious artefacts.
Personally, resizing all the time for printing is just a pain in the derriere. Leave the original images in their original highest quality state, do the photo-editing in Photoshop and the printing (at any size) out of Qimage.
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Drew, thanks for sharing this. It is interesting. I have two points about it though:
(1) One wonders why, with all the brilliant minds at Adobe, and Photoshop having gone through 9 versions over the past 20 years, they have not created resampling algorythms at least as good as QImage's. Perhaps there is no real explanation - just shows there will always be a niche for brilliant alternatives outside the four walls of the big corporations. Same reason why PixelGenius has sharpening algorythms that far surpass anything in Photoshop.
(2) On my monitor your full image is about 68 square inches. The blow-ups you then show are approximately 3 square inches of the original image. So there is an enlargement ratio of about 22.7x. That makes me wonder whether one would see any real difference of results between the two resampling tools on the full 68 sq.in. photograph without a loupe be it on the monitor or printed.
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Mark,
In response to your two specific questions I would say firstly, that after nine versions of Photoshop, it is still far from perfect. Adobe Bridge is a huge improvement over the file browser in CS, but that really is not saying much. The file browser in CS was completely rubbish. I must have cussed endlessly while it cached thumbnails for the first time and tied up Photoshop CS itself. There is no way it can have been properly tested with digital files of any sort of decent resolution. Even with Bridge, I find the handling of IPTC data clunky and on my sytems, it is a bit crash prone. I think the handling of printing is poor. I am not impressed by the 32 bit high dynamic range feature. I still get results more pleasing to me with layers and masks. The picture package feature again is absolutely not a patch on Qimage. Photomerge is a joke, especially if you compare it with the venerable Panotools with PTGui as the graphical front end. PTGui (was that Sergio's recommendation?) is absolutely brilliant. Very accurate and almost perfectly blended 16bit panoramas. I am also concerned that Adobe will take its eye off the ball needlessly developing a product to compete with Aperture (I am referring to Lightroom of course), when there is still a lot that could be improved in its main product for photographers i.e. Photoshop.
Secondly, my full image is not at all representative of the original file in that it has been downsampled and converted to sRGB for web display. The flatbed scans are just that, selective scans of portions of A4 inkjet prints of the full image in Adobe RGB 1998. If I were to make selective crops of the full size file, you would of course see much more detail, as below:
(http://www.pbase.com/drewbie/image/56162386.jpg)
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Drew, I agree with all that - added to which Bridge is also clunky and slows Photoshop. But I have to tell you, I went to a Lightroom Seminar yesterday afternoon here in Toronto given by Michael Reichmann - it was a three hour session on that program, and the program is GOOD. I'm on Windows so I can't use it yet, and it is still under development, but if you are on Mac, download it and try it. Miles ahead of Bridge, fast, easy, and it has some tools that are so cool they will probably end-up in future versions of Photoshop.
But on my second point, yes, that image you pointed me to is crystal clear - very good, no argument about it. But the question I was asking is different. If you were to re-rez the image in Photoshop (using the Image Size dialogue box, not Print with Preview) and then go back to the same file in its previous state and repeat the exercise in QImage, would one see a difference between the two full frame A4 prints with no further magnification? To put a finer point on it, I think if the term ever got into a dictionary, the dictionary definition of pixel-peeping would be where one is looking for differences between pixels under conditions that one would not normally look at the photographs. I don't look at photographs with a loupe or at 22x magnification. I just look at full photos, at normal viewing distance for the size of the image. So under these conditions, have you tested for and do you see an eye-popping difference between the same complete image (not a crop) at A3 or A4 size resampled with Photoshop "Image Size" tool versus resampled with QImage?
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My experiments weren't with text and drawn boxes, because that's not what I (and the vast majority of others here) are printing; my experiments were with a typical landscape photo. I'm not surprised that you might see a difference between 240 & 360 when you're looking at printed text, but that's pixel-peeping. For a normal landscape photo, I saw no difference, and that's what matters to me.
OK, if the printer is physically capable of resolving this difference to the naked eye (with the simple test I gave) and you're not seeing any differences from your D70 (or whatever) files, what does this tell you ... other than it probably makes little difference with your typical files/workflow?
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Mark,
I will do as you suggest and give Lightroom a spin.
What I have done is make another A3+ print from the original file using print with preview (so that the correct profile can be applied) and no scaling of the print. In other words a 300ppi image sent to the printer without any change in image size. I have compared this with the same file sent to the printer for an A3+ print using Qimage. I have scaled the image slightly in Qimage to fit the media better, so that the final printed image is actually slightly larger than the Photoshop print. Result? The Photoshop print still shows artefacts, admittedly slightly less severe than on the A4 print, but definitely still there. The Qimage print is perfect. Are the artefacts visible to the naked eye without the need of a loupe. Absolutely, yes
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Andrew, it is good of you to do that in aid of a discussion forum. I should do more of this testing myself, but what holds me back is the enormous amount of printing I've just completed over the past few months from a major photo-shoot, resizing my images to A4 or A3 in Photoshop (which almost always means reducing linear dimensions without resampling pixels, i.e. I'm resizing pixels rather than adding or subtracting them), then printing the images using the Epson driver and profile; honestly, I'm getting such clear, clean results that I'm having trouble relating to the problem, notwithstanding all the obviously objective evidence you have been producing. As I've mentioned above, there are definitely issues to deal with when severely cropping a 1Ds (1st or MKII) image and then trying to expand the remainder to A3, for example starting from something like 120PPI and aiming at 240 or more. Anyhow, this has been a very interesting discussion, and there is food for thought here in case of real tough nuts to crack out of the printer.
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Perhaps if Andrew would tell us which printer he has, we could see if there's a difference in the printers Mark, Lisa and Andrew use?
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Jani,
I used an Epson 7600 to make the prints in this instance, but I could also have shown examples from an Epson 4000 and a 2100 converted for black and white printing. I think there must be some problem with the handling of certain sizes of image out of photoshop, because the prints scaled up out of print with preview from film scans, which have small linear dimensions, but very high resolution look fine to me. There are no such issues with Qimage and I obviously like the very consistent way it handles print jobs.
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Jan, Andrew,
In the class of printers we're all using, the printer model clearly isn't a relevant factor - it is most likely the resampling algorythm. Andrew, I think part of the problem using Print with Preview to resample is that it can only use the default resampling algorythm that you specified in your Photoshop Preferences (General Tab, Interpolation). Hence if your preference there is specified as "Bicubic" you are depriving yourself of the technical advantages of Bicubic Smoother and Bicubic Sharper, which you can independently select according to specific image requirements if you were to activate your resampling using the "Image Size" dialogue box instead of "Print with Preview". (Likewise, by the way, "Transform" functions in Photoshop use only the default interpolation method specified in General Preferences.) Adobe developed the Smoother and Sharper variants to address limitations of Bicubic alone. This may partly explain the quality difference you see between Photoshop and QImage.
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Jan, Andrew,
In the class of printers we're all using, the printer model clearly isn't a relevant factor
Well, it could be that the printer drivers were significantly better for a new printer model as compared to a very old one; since Andrew didn't state what he used, and the qimage website refers to Photoshop 6, I was considering the possibility that there might be differences related to that.
That appears not to be the case.
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Mark,
I really do not know if Photoshop actually does resample out of print with preview or if it just does what the Qimage web info page says it does, which is just to chuck the job over to the Epson print driver and get it to fit the page. Either way it still does not explain what is happening when the image is sent to the printer without any change in size. Also, I find it very hard to believe that there really is any big difference between bicubic and bicubic smoother and bicubic sharper, certainly not enough to explain what I am seeing. Also, I take what you say about setting up in preferences, but often my printing is as much about scaling up as scaling down. As the thread has already indicated, sometines you will see these problems and sometimes you will not. Generally I find them whenever there is a very sharply defined and smooth line or curve, but in addition, having found this problem, I also find that the Qimage prints are very subtley better in other respects. Unless you have the two different versions in front of you, a lot of the time you will be satisfied with what photoshop does, especially if it is a landscape shot.
On the other side of the coin, if you are a PC user, a Qimage license is peanuts. Even if you are a Mac user, you can buy a PC with plenty of memory capable of running Qimage, network it to your Mac and run it through the switchable input of your Mac monitor and still have change out of the cost of a full photoshop license. If you subtract the cost of virtual PC, it would be even less.
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Drew,
How/when do you sharpen the image when printing from Qimage?
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Gordon,
Under the heading 'Prints' at top of page, go to 'print/Image interpolation". The options for final print sharpening are 'smart sharpening', 'normal sharpening' plus a slider that takes you from off, default, med to high.
What I find interesting about Qimage is the great choice of interpolation algorithms. I've been using the default 'Pyramid' algorithm which appears to be the best quality, but I've never bothered comparing any of them on actual prints. The list of options (with a 'quality' no. in parenthesis) is as follows:- Pyramid (10), Vector (8), Lanczos (7), Bicubic (6), Mitchell (5), Triangle (3), Hermite (3) and Bell (3).
Pyramid also has a slider that goes from smoother to sharper. Again, I've never bothered comparing the difference on prints. Maybe I should.
I'm puzzled that I cannot get Qimage to interpolate ppi to 720. It's always 360ppi (on my Epson 7600) with settings at maximum micro detail. But I have noticed that in certain circumstances it has interpolated an image to 720ppi in the past, but I can't remember what the conditions were. Not that it really matters. The great thing about Qimage is that it does all the work. The default settings have always seemed to be very acceptable to me.
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Gordon,
I'm puzzled that I cannot get Qimage to interpolate ppi to 720. It's always 360ppi (on my Epson 7600) with settings at maximum micro detail. But I have noticed that in certain circumstances it has interpolated an image to 720ppi in the past,[a href=\"index.php?act=findpost&pid=58405\"][{POST_SNAPBACK}][/a]
To the best of my knowledge all Epson wide format (ink lines) printers have a native res of 360 and all their smaller (piggyback cartridges) printers, 720. This is not mentioned on the QImage quality comparison page.
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Gordon,
I have to say I am not great advocate of sharpening for output. I tend to capture sharpen Canon digital files a bit in C1 Pro and I sometimes capture sharpen film scans when scanning with an Imacon precision II. I have Photokit Sharpener and I am familiar with other Photoshop methods such as the one John Brown described a few years ago on this website. I have never tried sharpening with Qimage and I tend to use it at default settings. All I can say is that I like my prints and I hope others do too. I particularly like them to look like my favourite wet prints from film.
I think sharpening is one of the most written about and abused tools in the digital box.
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Just to throw in more variables ...
I've been playing with the Lightroom beta with some raw files from a mate's Canon 5D. Lightroom has an option for "Print Resolution". I printed the same image with the Print Resolution set at 240dpi and 360dpi, deliberately leaving Enable Print Sharpening off. On Enhanced Matte at 2880dpi unidirectional, the 360dpi print was easily superior. The print sizes were chosen to ensure at least 360ppi of input data (the larger the print size is pushed, the smaller the differences one would expect). Assuming the algorithms stay the same for the shipping product, I can't see a reason why anybody would chose 240dpi. I haven't yet played around with any other values, nor compared this to what I can get out of Photoshop.
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To the best of my knowledge all Epson wide format (ink lines) printers have a native res of 360 and all their smaller (piggyback cartridges) printers, 720. [a href=\"index.php?act=findpost&pid=58408\"][{POST_SNAPBACK}][/a]
Thanks Dale. That must be the explanation. I've been using my old 1290 printer mostly for web pages and letters for a while now. However, there must have been an occasion recently when I used it for a print from Qimage and noticed the 720ppi interpolation.
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Thanks to those answering my question about when to sharpen in Qimage. I played around with Qimage once and found it useful for panoramics but then, as now, I was confused about final sharpening.
Part of my confusion is that I've bought into the Photokit Sharpener idea of capture, creative and output sharpening. It just made so much sense to me that I bought the package after very little testing and I've made almost no comparisons since then. I like and use Photokit Sharpener (I have no relationship with the company other than satisfied customer).
My routine workflow includes saving what I call a "pre-print" image and I even include "preprint" in the file name. That is, an image ready to print except for final sharpening. I suppose I could just trust Qimage to apply the appropriate sharpening but don't have the confidence to do so and don't want to do the testing to build up that confidence; hence, my question.
Qimage seems to be a good product and I do subscribe to the idea of (usually) not uprezing for larger prints so that aspect of Qimage is very interesting. And Drew's comparisons certainly have caught my eye...
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I suppose I could just trust Qimage to apply the appropriate sharpening but don't have the confidence to do so and don't want to do the testing to build up that confidence; hence, my question.
[a href=\"index.php?act=findpost&pid=58445\"][{POST_SNAPBACK}][/a]
Gordon,
No need to trust Qimage to do the final print sharpening. You can simply turn it off. There's a row of little boxes at the foot of the print preview.
However, I see the problem here if you are using Photokit Sharpener. In order to apply the final sharpening for the print size, you presumably have to rez up the image to it's final size and ppi first, in which case you are already doing the work that Qimage does for you automatically.