Question about rendering intents.

[ppage]

I use Photoshop and my working colour space is Adobe RGB. I want to get a large print done by a good print lab, but it’s a difficult image because some of the colours are out of gamut. The lab I’m considering offers ICC profiles to help select the best paper to use. I’ve soft proofed with their various profiles and selected the paper that gives the most acceptable results.

My problem is that even with the selected profile, the image looks different with different rendering intents and while it’s not bad with a relative colorimetric intent, it does look closer to what I want with a perceptual rendering intent. But while I can select a paper type when ordering, the rendering intent cannot be specified. The lab clearly states the following about using their ICC profiles “Make sure to only use these to proof your image and to never save or embed them to your file”.

I don’t see how the rendering intent can be communicated to the lab if the profile and rendering intent aren’t embedded in the file, and it’s clear that the rendering intent does make a significant difference. I emailed the lab in question several days ago but they never responded.

At this point I’m not sure how to proceed. Have I misunderstood something about ICC printer profiles and rendering intents or should I look for a better lab?

 

[technoid]

I've done some testing of i1Profiler profiles for a Baryta semigloss. Blackpoint is L*4 and white point L*98. Profiles were tested in Photoshop with the PhotoDisc image and also examined numerically in Matlab.

I made 4 profiles with the default settings and 16 bit with max grid size. Two were V4, and 2 were V2. They were made with Perceptual default settings (all 0) and also with the Colorful slider set at max (50).

No observable difference between the V4 and V2 profiles.

The Perceptual intents were examined and max colorful v default examined.

No evidence of "gamut compression." Colors that were in gamut were unchanged. However, there was a significant difference in colors that were out of gamut. These were all mapped to the gamut's surface. At low luminance levels, L* was increased and saturation increased because the printable gamut increases as L* goes up. The opposite occurs at high Luminance. There, the L* was decreased since the gamut gets larger at lower L* values.

The fact "colorfulness" made no difference can be seen in the colorchecker image contained in the Kodak Photodisc as the colors are all in gamut. No change at all in Photoshop switching between the profile with max colorfulness and default neutral.

However, a significant portion of the synthetic portions of the image show a very visible shift. These are all out of gamut colors. Particularly the brighter areas (L*>70) with strong colors. The colors darkened but also became much more saturated (or colorful) since the lower L* allows much greater a*/b* values.

There was no difference in the 4 kids at the bottom of the image.

There was a few areas with discernable differences. A dark brown case has colors slightly out of gamut and the "colorful" profiles slightly increased the luminance and increased saturation of the case.

All the visible differences were in areas where the image was out of gamut. They were shifted to appear more saturated by either decreasing L* in regions of high luminance or increasing L* in areas of low luminance. Both increase saturation because they shift OOG colors to the fatter part of the printer's gamut.

My major take is that the so called "gamut compression" that Perceptual is presumed to do is a myth. At least as far as Profiles created by i1Profiler.

Also, the white paper, I quoted earlier, describes an invertability in Perceptual, which requires gamut compression to do, has not been implemented in either V2 or V4 XRite profiles. So indeed, NAwlins Contrarian's observations are correct. Probably worth noting that the white paper's algorithm is not reflected in the actual ICC specification document. Details of how the Perceptual Intent, unlike Colorimetric Intents, are implemented are up to the vendor.

 

[the-ninth]

Sort of. While you are in ProPhoto RGB space, the actual colors are correctly represented but the display of Lab is not.

So, you are saying when using the color picker in an image in the ProPhoto RGB color space, the shown RGB value represents the color in the ProPhoto RGB color space, while the Lab value represents the same color in the Lab color space?

 

[the-ninth]

The reason for my rejection of this sort of progression/regression is that after over 35 years as a professional magazine and corporate photographer , all I see are pseudo imagers debating the ar$e off minute and frankly silly points when the fundamentals of making an interesting and artistic image elude them.

What you can obviously see in this thread is people being interested in the finer technical details of the printing craft. But what in the discussion gives ground for your devaluation of the artistic aspects of our work, apart from a healthy dose of arrogance on your part?

 

[kciuk aka Ken60]

I think your snaps might be "work" when you earn a living from them ! As for arrogance ......

 

[the-ninth]

I think your snaps might be "work" when you earn a living from them !

Earning a living from photography does not necessarily speak for the artistic value of one‘s work. I have seen too many „professionals“ producing mediocre output to believe that, and too many „amateurs“ with extraordinary portfolios.

But enough said about this, let‘s just all pursue those lines of discussions that are interesting for us and try to tolerate those that are not …

 

[technoid]

Sort of. While you are in ProPhoto RGB space, the actual colors are correctly represented but the display of Lab is not.

So, you are saying when using the color picker in an image in the ProPhoto RGB color space, the shown RGB value represents the color in the ProPhoto RGB color space, while the Lab value represents the same color in the Lab color space?

The Lab values for ProPhoto RGB are correct so long as the a* and b* are from -128 to 127. The displayed values are clipped when the ProPhoto's RGB exceed those limits. If you convert to Lab space that clipping is applied to the image.

 

[the-ninth]

The Lab values for ProPhoto RGB are correct so long as the a* and b* are from -128 to 127. The displayed values are clipped when the ProPhoto's RGB exceed those limits. If you convert to Lab space that clipping is applied to the image.

I really thought this works differently, but after testing it a bit more it seems you are right. It really seems that the Lab values in the color picker do represent the color in the Lab color space.

I was then wondering what about the RGB values, because there are multiple RGB color spaces. It seems when in an RGB color space, they obviously refer to that color space, but when in a different color space like Lab, they refer to the RGB space that is configured as RGB working space in the color settings.

So, thanks for being patient with me, I am happy to have learned something today.

 

[ppage]

But enough said about this, let‘s just all pursue those lines of discussions that are interesting for us and try to tolerate those that are not …

Agreed. Catch any one of us at the right moment on the wrong day and we're likely to dash off a nasty post that is not necessarily wrong, but might have been phrased more diplomatically. I've certainly done that. We (actually in this case "I") should try to remember that a post that takes 10 seconds to write and is then read without any further context is not enough to warrant jumping to conclusions about another person's nature, their interests, their abilities, or their knowledge and experience.

 

[ppage]

Also, FWIW, you probably ought to work in ProPhoto RGB because there are some colors that are outside of Adobe RGB that many printers can print. Of course, if you have to submit the files in a smaller working space like Adobe RGB or sRGB, that may not help any, but some services let you submit in ProPhoto RGB.

Still on my quest for a decent photo lab, but came across this video which tends to suggest I might be right to stick with Adobe RGB. Thought I'd mention it here in case you're interested.

 

[the-ninth]

Still on my quest for a decent photo lab, but came across this video which tends to suggest I might be right to stick with Adobe RGB. Thought I'd mention it here in case you're interested.

To be honest, better ignore the advice from that video.

I would also recommend ProPhoto RGB as working color space. Nowadays you‘ll find both monitors and printers that can display or print colors beyond Adobe RGB. I once did some tests on this, you can find the results here:

Why ProPhoto RGB as Working Color Space? - Blog - The Ninth - Why ProPhoto RGB as Working Color Space?

Showing the differences between the working color spaces ProPhoto RGB, Adobe RGB and sRGB, and why they matter in relation to gamuts of high-end monitors and inkjet printers.

www.the-ninth.com

Regarding his comment on gradients, he is right about that, that is why when using ProPhoto RGB you should also always use 16 Bit files instead of 8 Bit files, which gives you plenty of room for smooth gradients. Drawback of this are of course larger file sizes.

But of course the difference between Adobe RGB and ProPhoto RGB is not what is going to make or break your image or print. But still, if you have that wide gamut monitor or that high end printer, why limit it with your workflow? Additional advantage is that the larger color space and color depth give you more room to maneuver if you do extensive post processing.

Two more notes on the video: first, he is talking a lot about setting sRGB or Adobe RGB in the camera - this is only relevant if you shoot JPEG, RAW files do not use either of those color spaces. Second, he uses the Assign Profile function in Photoshop, which does not convert the colors from one space to another, it uses the same color values, which of course represent different colors in a different color space. Normally you‘d use the Convert function, which keeps the colors stable when going to a larger space and offers you different methods (rendering intents) to compress colors when going to a smaller space.

 

[Philip Eihuyar]

Still on my quest for a decent photo lab, but came across this video which tends to suggest I might be right to stick with Adobe RGB. Thought I'd mention it here in case you're interested.

To be honest, better ignore the advice from that video.

I would also recommend ProPhoto RGB as working color space. Nowadays you‘ll find both monitors and printers that can display or print colors beyond Adobe RGB. I once did some tests on this, you can find the results here:

https://www.the-ninth.com/blog/prophoto-for-image-editing

Regarding his comment on gradients, he is right about that, that is why when using ProPhoto RGB you should also always use 16 Bit files instead of 8 Bit files, which gives you plenty of room for smooth gradients. Drawback of this are of course larger file sizes.

But of course the difference between Adobe RGB and ProPhoto RGB is not what is going to make or break your image or print. But still, if you have that wide gamut monitor or that high end printer, why limit it with your workflow? Additional advantage is that the larger color space and color depth give you more room to maneuver if you do extensive post processing.

Two more notes on the video: first, he is talking a lot about setting sRGB or Adobe RGB in the camera - this is only relevant if you shoot JPEG, RAW files do not use either of those color spaces. Second, he uses the Assign Profile function in Photoshop, which does not convert the colors from one space to another, it uses the same color values, which of course represent different colors in a different color space. Normally you‘d use the Convert function, which keeps the colors stable when going to a larger space and offers you different methods (rendering intents) to compress colors when going to a smaller space.

I found the video useful for my basic understanding of 3 dimensional graphs of a colorspace as well as the negatives of Pro-photo conversions. A question I have is when editing, I sometimes convert to L.AB space in curves to bring more saturation and contrast. I do not understand how that works. What is the difference between L.AB and Adobe RGB

 

[ppage]

Still on my quest for a decent photo lab, but came across this video which tends to suggest I might be right to stick with Adobe RGB. Thought I'd mention it here in case you're interested.

To be honest, better ignore the advice from that video.

I would also recommend ProPhoto RGB as working color space. Nowadays you‘ll find both monitors and printers that can display or print colors beyond Adobe RGB. I once did some tests on this, you can find the results here:

https://www.the-ninth.com/blog/prophoto-for-image-editing

Regarding his comment on gradients, he is right about that, that is why when using ProPhoto RGB you should also always use 16 Bit files instead of 8 Bit files, which gives you plenty of room for smooth gradients. Drawback of this are of course larger file sizes.

But of course the difference between Adobe RGB and ProPhoto RGB is not what is going to make or break your image or print. But still, if you have that wide gamut monitor or that high end printer, why limit it with your workflow? Additional advantage is that the larger color space and color depth give you more room to maneuver if you do extensive post processing.

Two more notes on the video: first, he is talking a lot about setting sRGB or Adobe RGB in the camera - this is only relevant if you shoot JPEG, RAW files do not use either of those color spaces. Second, he uses the Assign Profile function in Photoshop, which does not convert the colors from one space to another, it uses the same color values, which of course represent different colors in a different color space. Normally you‘d use the Convert function, which keeps the colors stable when going to a larger space and offers you different methods (rendering intents) to compress colors when going to a smaller space.

I always shoot RAW; I have a wide gamut monitor that I calibrate regularly, I save my edited files as 16 bit TIFFs, but I don't own my own printer; I don't print enough to warrant it.

So this is the crux of the problem. I have an image that looks fine on my monitor and I want a large print of that image. I'm only considering labs that say they accept Adobe RGB and that offer printer profiles. I haven't found any labs that say they accept a wider colour space. When I soft proof using those printer profiles the papers (and/or the printers) can't reproduce the depth of the colours in the image irrespective of which paper or rendering intent I use.

I am willing to compromise somewhat and accept an image that is less that what I'd like but it depends on being able to specify the rendering intent in my print order. The lab I was considering, while allowing me to specify a paper (selected after working with their printer profiles) does not allow me to choose a rendering intent nor do they tell me which rendering intent they would use. (And emails to them go unanswered.)

Thank you for your thoughtful reply, especially for the explanation of the difference between assigning a profile and converting to one. The information on the page you wrote ("Why ProPhoto RGB as Working Color Space?") was very informative and makes a lot of sense but I still am struggling with one point. If I work in ProPhoto RGB but my monitor can't display that full colour space, how can I edit accurately and anticipate the print results when I send a file to a printer that exceeds Adobe RGB? For example: should I push the saturation of one colour channel to 100% will the colours in that channel not come back more saturated in the print than I expected? (And I do understand that a print will never match exactly with my monitor as they are two very different media).

 

[the-ninth]

If I work in ProPhoto RGB but my monitor can't display that full colour space, how can I edit accurately and anticipate the print results when I send a file to a printer that exceeds Adobe RGB? For example: should I push the saturation of one colour channel to 100% will the colours in that channel not come back more saturated in the print than I expected? (And I do understand that a print will never match exactly with my monitor as they are two very different media).

That is a very good point and definitively something to watch out for when working with highly saturated colors.

When I compared the color space of my monitor to that of my printer, there were some areas exceeding Adobe RGB that both devices could display/print, but also some that only the printer could handle (see section "Monitor and Printer Comparison" in the blog post). For those areas you'd be flying blind, so to speak.

But, depending on what tools you use for editing, not completely blind. Photoshop and Lightroom can help you identify such areas and then you can decide what to do about them. When you do Soft Proofing in Lightroom (which btw always uses a ProPhoto RGB variant in the develop module as working color space), you can activate overlays that show you any colors exceeding the monitor's color space and any colors exceeding the printer's color space. In Photoshop it is a bit more complicated, in soft proofing there is only a gamut warning for the printer profile. However you can soft proof with the monitor profile as target and then the gamut warning will show you any areas of the image that is out of the monitor's gamut.

Personally in my own photography I have not experienced this too be a big problem. Generally in my images the areas that exceed either the printer or the monitor color space are usually relatively small. Relying on the rendering intent to bring them back in usually works for me, I rarely feel the need to do that by explicit editing.

And yes, for those areas what you see on the screen will not match the print, but like you said, the print is anyway not what you see on the screen, and I think such differences in gamut size and how the rendering intents for screen and printer handle them are only a relatively small contributing factor to that.

Of course others with different image styles might encounter the issue more frequently and in larger areas of their images, requiring different strategies on how to deal with them.

 

[kciuk aka Ken60]

When you calibrate your monitor before profiling it , try setting the calibration to no higher than 100 cdm2 , gamma 2.2, and white point D65 ( these are basic norms, Then when selecting the gamut , use Native instead of aRGB . This presumes that your monitor can produce colours outside of the Adobe RGB 1988 colour space , and thus it will produce a profile that allows it to offer its full potential.



When you look at the above graphic you can see that the Video space of DCI P3 is a "wide" space as is aRGB , however they both cover shades that the other omits. What Native creates is a mapped gamut for the full ability of your monitor , after all if the monitor cant reach say the deepest greens , calibrating for Adobe RGB will not change this. Native uses everything you can achieve and the rest will be adapted to offer the best indication. Depending on the printer used , and how they use it , it is possible nowadays to print shades outside of aRGB even though not all that it covers.... again adaption is used to render wayward shades.

Darn pity that through these forums , or a local photographic society you can not find a like minded spirit that has a capable printer , and for some help with ink costs might enjoy a higher throughput , and possibly allow you to join in and experience the practice of producing your own prints.... and having the control you need .

 

[ppage]

When you calibrate your monitor before profiling it , try setting the calibration to no higher than 100 cdm2 , gamma 2.2, and white point D65 ( these are basic norms, Then when selecting the gamut , use Native instead of aRGB . This presumes that your monitor can produce colours outside of the Adobe RGB 1988 colour space , and thus it will produce a profile that allows it to offer its full potential.

My monitor is a BenQ SW320. I calibrate it to 70 cdm2, gamma 2.2, D65, and Native rather than Adobe RGB although I use Adobe RGB as my colour space in Photoshop. I also use a white background and a light colour scheme in Photoshop so that my eye won't be misled with respect to the colours or the tone of my image. I think I'm doing everything I can to manage colour properly, but short of buying and feeding a printer of my own, I am at the mercy of photo labs.

Darn pity that through these forums , or a local photographic society you can not find a like minded spirit that has a capable printer , and for some help with ink costs might enjoy a higher throughput , and possibly allow you to join in and experience the practice of producing your own prints.... and having the control you need .

The demand is there I think for an online service that gives the control many of us would like to have; it's disappointing that I can't find it. To be perfectly honest, I may be obsessing about this one image because I've used a local lab before and had no trouble even though they didn't supply printer profiles. Unfortunately that lab is gone now, and I suspect this one image would not have been printed very well by them either.

 

[kciuk aka Ken60]

Despite all the theoretical impacts of numerical constructions , sometimes the s--- just wont work. I have had an image recently from a set taken in Iceland. One beach shot rendered areas of the sky and water where it crashes on the beach, as a shade of cyan ! No such shade existed in the image, yet whatever I did this reproduced badly ... suffice to say my monitor is an Eizo and well calibrated internally and the paper profiles are custom made by a professional source .

I played all corners of this game to try and figure the error / conversion etc that might have caused this including using alternative paper. It is just one of life's quandary's, and in the end I selected the offending colours and created layers in Photoshop to duplicate and isolate this shade. Once I had control I altered the colour and feathered the masks to hide and blend the changes.

Once reprinted I was pleased to see the colour achieved in this area was that I remembered and suited the image. Guess what I am trying to say is the life is sometimes unfair, however if you have the tools skills and ability to take the issue on practically you can achieve what looks normal.

Though perhaps not everyone's choice of play, I find duplicating the image, and setting the screen to show two side by side is a great way to judge. In photoshop once you have introduced your paper profile use Ctrl + Y to soft proof on of the pair and then use your tools to work comparing with the non soft proofed version.

 

[the-ninth]

ppage wrote:
The demand is there I think for an online service that gives the control many of us would like to have; it's disappointing that I can't find it.

Apologies if it has been mentioned before, but have you checked out Whitewall? It is a German high-end online photo lab, and they also deliver overseas, including to Canada.

Bestes Fotolabor - WhiteWall | TIPA Gewinner 2025

Online & Store | Fotolabor für Fotografen | ►Ihr Foto › hinter Acrylglas › auf Alu-Dibond › Gerahmt ✓ Fotoleinwände, Fotobücher, Fotokalender & mehr gestalten bei ⬜ WHITEWALL

www.whitewall.com

Also I have to say I am really surprised that in a city like Montreal there is no local photo lab that you could work with.

 

[ppage]

Despite all the theoretical impacts of numerical constructions , sometimes the s--- just wont work. I have had an image recently from a set taken in Iceland. One beach shot rendered areas of the sky and water where it crashes on the beach, as a shade of cyan ! No such shade existed in the image, yet whatever I did this reproduced badly ... suffice to say my monitor is an Eizo and well calibrated internally and the paper profiles are custom made by a professional source .

I played all corners of this game to try and figure the error / conversion etc that might have caused this including using alternative paper. It is just one of life's quandary's, and in the end I selected the offending colours and created layers in Photoshop to duplicate and isolate this shade. Once I had control I altered the colour and feathered the masks to hide and blend the changes.

Once reprinted I was pleased to see the colour achieved in this area was that I remembered and suited the image. Guess what I am trying to say is the life is sometimes unfair, however if you have the tools skills and ability to take the issue on practically you can achieve what looks normal.

Though perhaps not everyone's choice of play, I find duplicating the image, and setting the screen to show two side by side is a great way to judge. In photoshop once you have introduced your paper profile use Ctrl + Y to soft proof on of the pair and then use your tools to work comparing with the non soft proofed version.

It's nice to know I'm not the only one who gets obsessed with being able to print an image the way I want it.

I don't use the duplicate image technique for comparisons, though it's a good one. In a situation like this I'll group my adjustments layers on top of the image and toggle the group on and off. It makes it easier for me to see exactly what is happening in any particular area of the image. It's a personal choice. I do use Ctrl-Y when soft-proofing; this particular image is way out.

 

[ppage]

ppage wrote:
The demand is there I think for an online service that gives the control many of us would like to have; it's disappointing that I can't find it.

Apologies if it has been mentioned before, but have you checked out Whitewall? It is a German high-end online photo lab, and they also deliver overseas, including to Canada.

https://www.whitewall.com

Thank you for this link. No one had mentioned it. I did come across a reference to it somewhere else but I didn't realize they'd ship to Canada. I'll look into it.

Also I have to say I am really surprised that in a city like Montreal there is no local photo lab that you could work with.

So am I. There are actually several labs that might be good here in Montreal, but none of them offer printer profiles on their sites and most of them give little information of how to prepare a file. One of the better ones for example simply says for best results the image should be "300 dpi resolution, sRGB or Adobe RGB 1998, JPEG or TIF 8-bit format without layers". I'm waiting for answers to emails I've sent to a couple of these local labs about printer profiles.

 

[ppage]

ppage wrote:
The demand is there I think for an online service that gives the control many of us would like to have; it's disappointing that I can't find it.

Apologies if it has been mentioned before, but have you checked out Whitewall? It is a German high-end online photo lab, and they also deliver overseas, including to Canada.

https://www.whitewall.com

This looks very promising. The information they offer on their site about the use of icc profiles is much more complete than what I've found at other labs. Like other labs, they also don't allow me to specify a rendering intent, but at least they tell me which rendering intent they will use (relative colorimetric).

Thank you again.
Peter