what is the relation/difference between printer resolution, say 28800 DPI and in LR, say, 360 PPI? How can you calculate for a given size of a print, what amount of PPI and DPI should be chosen for having the best possible fine art print? I have read Jeff Schewe Digital Print, but either I could not understand or he misses to elaborate the matter; In page 129 of his book, comparing iPhone with P65 print resolution, he says the iPhone resolution is not sufficient to print 18.7x24.9 because resolution comes down to 132PPI; okay but what is the calculation Jeff? How do you find out? in LR, when you change the print size in Print module and print resolution tab is unchecked, resolution of print changes while you change the print size and it shown on the upper left side of the picture; what is the formula? how LR calculate that? when you check the resolution tab in LR and changing the print size, how should I find out what resolution should I chose for a given print size for best quality?
thanks Slobodan but give me an example; file size of RAW or tiff or doesn't matter?
How do you find out? in LR, when you change the print size in Print module and print resolution tab is unchecked, resolution of print changes while you change the print size and it shown on the upper left side of the picture; what is the formula? how LR calculate that? when you check the resolution tab in LR and changing the print size, how should I find out what resolution should I chose for a given print size for best quality?
Thanks a lot Jeff! not confused any more but just assume that I have D800 with native resolution of 7360 so I can print as big as 20" with 360 PPI but what if I like to print the same file on 40" paper with same 360PPI? Is it possible at all?
There is something called Vernier acuity, the eye can detect discontinous lines, even if the displacement is lower than normally resolved. So for images with lines, or well defined edges 720 PPI may be helpful.I have seen this point raised a few times. I have never seen it discussed related to "proper" (re)sampling.
I have seen this point raised a few times. I have never seen it discussed related to "proper" (re)sampling.
If your camera has "proper" pre-filtering, and your printer/display apply the equivalent of proper post-filtering, then a thin-ish line can be displaced by subpixel amounts. Of course, the sampling systems (and resampling) of imaging leaves a lot to be desired, but it is not simple point-samplers, either.
Hi,Not sure if you are saying that Vernier acuity can be used for estimating thresholds of visible distortion or not?
Proper resampling will require subsequent (deconvolution) sharpening to remove some of the resampling blur. The required PSF can be approximated by resampling a slanted edge and analyzing the result.
Cheers,
Bart
Are you guys serious!?
Not sure if you are saying that Vernier acuity can be used for estimating thresholds of visible distortion or not?
Vernier acuity exceeds normal (20/20) visual acuity. It depends on the subject/micro-contrast how significant Vernier acuity is for the output, but up-sampling will lower the PPI limit of 20/20 vision, so it's best to properly sharpen after up-sampling to keep as much intact as possible.If one is to reproduce figures like the one below, using a camera and display/printer, I think that proper (linear) filtering is more important than fancy nonlinear processing. Yes, the end-to-end filtering will cause blurring, but the whole point of Vernier seems to be that the width and exact shape of the line does not matter as much as its placement. So a certain amount of blurring should be visually transparent (at some scale, say on the order of 1 minute of arc or some fraction of that. What matters (wrgt Vernier) is that the weight of the line can be recorded and recreated accurately.
Upsampling algorithms like Photozoom's S-Spline Max, will add resolution and that may help even more.
Oh, I see, you ARE serious.
A guy stops to asks for directions to the nearest gas station, and you engage in a post-doctoral dissertation on the properties of space rocket fuel!?
What matters (wrgt Vernier) is that the weight of the line can be recorded and recreated accurately.
Yes, and with adequate contrast. But that leads to stating the obvious, that nothing beats real resolution, and that lacking that we need proper re-sampling, and proper sharpening.Bumping real resolution is a "trivial fix" to the problem, but does not seem to really answer the OPs question:
...How can you calculate for a given size of a print, what amount of PPI and DPI should be chosen for having the best possible fine art print?...Rather, the question seems to be "how low can you go on resolution while still having no visual loss" (I am assuming a properly chosen angular resolution metric). An often quoted figure is 1 minute of arc, something that can be related to the elements of letters used for establishing 20/20 vision:
Bumping real resolution is a "trivial fix" to the problem, but does not seem to really answer the OPs question: Rather, the question seems to be "how low can you go on resolution while still having no visual loss" (I am assuming a properly chosen angular resolution metric).
A common counter-argument is that Vernier acuity extends the limit to 0.13 arc minutes (for special case images).
I believe that you cannot have both high contrast and linear-filter-like degradation in a sampling system as you approach fs/2.
The anti-OLPF, 1:1 pixel viewing afficionados seems to prioritize high contrast, while others prioritize linear behaviour. If we are to discuss what bandwidth is "necessary", we have to also discuss (like you seem to allude to) the properties of capture, processing and rendering beyond mere passband width.
Hi,
posted about a tool
So what's actually needed to answer the question is a complete system MTF calculation, from scene contrast, to capture device, to post-processing, to viewing distance, to output medium MTF and surface structure.
Cheers,
Bart
In terms of the difference between image resolution and printer resolution, the output resolution of printers refers to droplets/inch. So, at 2880 the Epson printers put 2880 droplets of ink/inch. In terms of dots/inch, that's a different measurement–printers report their resolution to the print pipeline as dots/inch (DPI) which is a different measurement unit...Epson printer report 360 DPI which Canon HP report 300 DPI. There are driver modes that can change the reported resolution; Finest Detail makes Epson printers report 720 DPI while Canon & HP can be set to report 600 DPI.
Confused yet? Go back and reread the section in the book...
That could become a nice Android App.
Pity that no output media MTFs are published.
In terms of the resolution you "need" for a print, that depends on viewing distance because human vision resolution is dependent on the viewing distance. The close you hold a print to your eyes, the more resolution that your eyes can resolve. There's a chart on page 129 that tells you the eye's resolvable resolution. A couple of examples: viewing distance of 8 inches would require 428 PPI in PPI resolution. From 18 inches you would need 191 PPI.
In terms of determining the usable range of output resolution, Bruce thought that depending on print size, you needed at least 180 PPI to a max of 480 PPI. However, I've found that depending on the printer, you can tell the difference up to about 720 PPI (assuming Epson, or 600 PPI for Canon or HP). This type of resolution is really only useful for small prints–which is handy because you'll have higher output resolution when making small sized prints.
In terms of the difference between image resolution and printer resolution, the output resolution of printers refers to droplets/inch. So, at 2880 the Epson printers put 2880 droplets of ink/inch. In terms of dots/inch, that's a different measurement–printers report their resolution to the print pipeline as dots/inch (DPI) which is a different measurement unit...Epson printer report 360 DPI which Canon HP report 300 DPI. There are driver modes that can change the reported resolution; Finest Detail makes Epson printers report 720 DPI while Canon & HP can be set to report 600 DPI.
For 360 DPI, what resolution in terms of PPI is needed in our image? If we were resizing manually in Photoshop, what resolution in terms of PPI would be needed?
I have not done any testing to determine what the least amount of resolution would be required...back when Bruce and I did PhotoKit Sharpener, we determined that 180 PPI would be the minimum prior to upsampling.
For 360 DPI, what resolution in terms of PPI is needed in our image? If we were resizing manually in Photoshop, what resolution in terms of PPI would be needed?
In 2008, with the arrival of the Epson 3800, we (5 of us in the studio) carried out a rough&ready test on both pearl and glossy paper to see if we could actually observe any difference in output. We used Nikon's promo images for the D3 , exposed at 200-1600-3200 ISO, to avoid any in-house bias.
Output was onto both glossy and pearl A4 paper at 360, 255 and 180 dpi. Photo black no matt. Printer set to 1440 ( native 360 dpi). Printed through photoshop, (no resizing through the epson driver). Both colour and B&W – not ABW.
In B&W, under close inspection , including an 8x lupe, none of us could see any discernible difference between the different resolutions. In colour opinions differed. There was minimal difference , but arguably some felt that there was a difference in areas of continuous monochrome colour such as the blue of the baseball bats photo.
The conclusion, was that there was no visible difference above 250 dpi, and effectively 180 dpi output was identical to the higher resolutions, certainly in B&W. Today, due to the much improved resize algos and increased sensor mpx, I output at 360dpi – but if I wanted to go really large 180 dpi wouldn't worry me.
Again, I think there is some confusion here …
I duplicated and then resized (downscaled) the images outside photoshop to 255 and 180. I then printed them through photoshop at their new native resolutions – but yes, the Epson driver would have resized them to the printer's native resolution, in this case 1440 (360dpi).
I think the only way to really test this would be to use images shot with the same lens on the same size sensors with different photosite density. 36MP/24MP/16MP, but even then you'd have variations from the sensor microlenses and the AA filter.
How do you know how much to sharpen the file if you send it to an outside printer?
How do you know how much to sharpen the file if you send it to an outside printer?
I'm always encouraged when discussions get to this level. It lets me know that this Forum has real depth of expertise. Please continue.
In terms of the difference between image resolution and printer resolution, the output resolution of printers refers to droplets/inch. So, at 2880 the Epson printers put 2880 droplets of ink/inch. In terms of dots/inch, that's a different measurement–printers report their resolution to the print pipeline as dots/inch (DPI) which is a different measurement unit...Epson printer report 360 DPI which Canon HP report 300 DPI. There are driver modes that can change the reported resolution; Finest Detail makes Epson printers report 720 DPI while Canon & HP can be set to report 600 DPI.
Confused yet? Go back and reread the section in the book...
The reported resolution should be in PPI but most drivers do not use that either. The "Maximum DPI" print quality setting in the HP B9180 driver asks for 1200 PPI input. I guess that some desktop Canons do the same. Even the old driver/firmware of the HP Z3100 had a print quality setting that asked for 1200 PPI input. It dropped to 600 PPI with the latest driver/firmware version. The humble HP K5400 Officejet Pro asks for 1200 PPI input with the highest print quality setting on photo paper. Probably a bit optimistic for that machine.
Possible exceptions are… or Photozoom Pro (http://www.benvista.com/photozoompro) which adds edge resolution that really helps certain images by actually adding high resolution detail.
Thanks Jeff and Bart. It doesn't appear that Photokit sharpener 2 is compatible with LR3 which I'm using. I forgot to mention that I want to scan 6x7's chromes that will be printed. So I guess the best things would be to meet with the pro scanner/printing company (in NYC) and get their advice directly for both processes before I waste a lot of time and money. Any suggestions along that line for the right questions to ask them?
Thanks Jeff and Bart. It doesn't appear that Photokit sharpener 2 is compatible with LR3 which I'm using.Not sure what you mean. PhotoKit has never been part of the LR workflow. Now LR's sharpening workflow IS based on PhotoKit Sharpener! Capture and Output Sharpen either in Photoshop using PKS or Capture Sharpen and Output Shapren in LR using it's tools, based on PKS. What LR doesn't really have (certainly no where near the degree of Photoshop and PKS) is creative sharpening.
Bart,
Yes, I do use Photozoom Pro, having moved onto it from Genuine Fractals (as it was known then). But could you expand on how it 'actually adds high resolution detail' - as opposed to simply interpolating the data ?
Maybe you've seen this thread (http://www.luminous-landscape.com/forum/index.php?topic=62609.msg505337#msg505337), where I've measured and plotted some MTF response curves ...
Not sure what you mean. PhotoKit has never been part of the LR workflow. Now LR's sharpening workflow IS based on PhotoKit Sharpener! Capture and Output Sharpen either in Photoshop using PKS or Capture Sharpen and Output Shapren in LR using it's tools, based on PKS. What LR doesn't really have (certainly no where near the degree of Photoshop and PKS) is creative sharpening.
You could mix and match depending on your workflow. Capture Sharpen raws in LR, apply output sharpening in Photoshop and print there (or LR without adding more sharpening).
PKS is a Photoshop plug-in and to be used only there but when you decide to use it is up to your workflow.
I would love to have a parametric version of PKS integrated into Lightroom.It's been there for years. Again what's 'missing' is creative sharpening and since you may be doing a lot of selective work here, painting and masking, best done in Photoshop. At least with the current technology (do lots of local parametric editing, you see how things bog down).
Why are you still using LR3? LR5.3 is vastly improved and reasonably priced either as the cloud version with Photoshop or as a perpetual license. It incorporates the functionality of Photokit2. It would seem a no brainer to me.
Win 7 should run on anything that ran Vista, just as aside - and run better.
Why are you still using LR3? LR5.3 is vastly improved and reasonably priced either as the cloud version with Photoshop or as a perpetual license. It incorporates the functionality of Photokit2. It would seem a no brainer to me.
Perhaps Bart can clarify.
Bill
Hi M,
Maybe you've seen this thread (http://www.luminous-landscape.com/forum/index.php?topic=62609.msg505337#msg505337), where I've measured and plotted some MTF response curves and up-sampled image crops. Poster Joofa added a FFT overlay which demonstrated that indeed more high spatial frequency detail was added by Photozoom.
Cheers,
Bart