Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
10-26-2017, 05:14 PM   #1
Senior Moderator
Loyal Site Supporter
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: Durham, England
Posts: 9,818
Colour me shocked!... Limitations of screen vs. web vs. printed vs. film colour gamut

This is something of a newbie question re colour gamuts, so apologies if it's a dumb one... please cut me a little slack!

As part of my very recent trialling of Darktable under Linux as a replacement for Lightroom, I've been playing around with some older images from various different cameras.

This evening, I've been working with some test shots I took with my Hasselblad HV ("Sony A99"), of some pretty yellow pansies in my back garden.

Upon exporting them as 8-bit JPEG using web-safe sRGB as the output colour profile, I noticed that the yellows (in particular) were really under-saturated... they looked almost "milky" compared to the rich, bright yellows I could see on screen. Darktable has really great soft-proofing and gamut check facilities, much like Lightroom except that you can engage them during live editing (maybe that's possible with Lightroom too, but I've never done it). Sure enough, those tools showed that the lovely, rich yellows I could see on my screen were outside of the gamut for my chosen output profile. And, the other available output profiles (AdobeRGB etc.) weren't hugely different.

For the first time, I started to research the gamuts for sRGB, Adobe RGB, and even Prophoto RGB, and I was shocked by how limited they are.

My question is this:

Is "Prophoto RGB" (or any other professional printing colour profile) capable of reproducing the colours I see on-screen during editing, or is the on-screen view of my processed RAW the best I'll ever see - with all other output formats and media being somehow reduced or inaccurate in terms of colour reproduction?

And a related observation: I assume there must be colours that certain film / dye / paper combinations can produce that simply can't be reproduced via printed digital images... and, if so, this is potentially a key difference between digital and film photography (depending on the developing and printing processes used)?


Last edited by BigMackCam; 10-26-2017 at 05:23 PM.
10-26-2017, 05:27 PM - 1 Like   #2
Loyal Site Supporter
Loyal Site Supporter




Join Date: Apr 2010
Location: Tennessee
Posts: 6,083
QuoteOriginally posted by BigMackCam Quote
This is something of a newbie question re colour gamuts, so please cut me a little slack...

As part of my very recent trialling of Darktable as a replacement for Lightroom, I've been playing around with some older images from various different cameras.

This evening, I've been working with some test shots I took with my Hasselblad HV ("Sony A99"), of some pretty yellow pansies in my back garden.

Upon exporting them as 8-bit JPEG using web-safe sRGB as the output colour profile, I noticed that the yellows (in particular) were really under-saturated... they looked almost "milky" compared to the rich, deep yellows I could see on screen. Darktable has really great soft-proofing and gamut check facilities, much like Lightroom except that you can engage them during live editing (maybe that's possible with Lightroom too, but I've never done it). Sure enough, those tools showed that the lovely, rich yellows I could see on my screen were outside of the gamut for my chosen output profile. And, the other available output profiles (AdobeRGB etc.) weren't hugely different.

For the first time, I started to research the gamuts for sRGB, Adobe RGB, and even Prophoto RGB, and I was shocked by how limited they are.

My question is this:

Is "Prophoto RGB" (or any other professional printing colour profile) capable of reproducing the colours I see on-screen during editing, or is the on-screen view of my processed RAW the best I'll ever see - with all other output formats and media being somehow reduced or inaccurate in terms of colour reproduction?

And a related observation: I assume there must be colours that certain film / dye / paper combinations can produce that simply can't be reproduced via printed digital images... and, if so, this is potentially a key difference between digital and film photography (depending on the developing and printing processes used)?
What monitor do you have? Is it color calibrated? Most decent monitors cover about 98% of the sRGB space. You have to go to more premium monitors to get to Abobe RGB or Pro at 100% coverage. The next question is about your printer. Ink? Paper? Color profile used? Most paper manufacturers provide profiled for their paper with factory ink. If you are using 3rd party ink with 3rd party paper you will need to create a color profile. Dyes offer more vivid colors than pigments (typically), but pigments have a longer life (typically).

If you want to get into color management then you need to create a color profile for your camera/lens combination. Calibrate your monitor, and you need a printer that is also profiled and has the color gamut you need.

Why You Should Probably Use sRGB

Most people viewing your images on the web won't have any of this, so sRGB is your best bet for showing the general public.

https://www.diyphotography.net/x-rite-announces-new-i1studio-end-end-colour-...photographers/
10-26-2017, 05:37 PM   #3
Senior Moderator
Loyal Site Supporter
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: Durham, England
Posts: 9,818
Original Poster
QuoteOriginally posted by Winder Quote
What monitor do you have? Is it color calibrated? Most decent monitors cover about 98% of the sRGB space. You have to go to more premium monitors to get to Abobe RGB or Pro at 100% coverage. The next question is about your printer. Ink? Paper? Color profile used? Most paper manufacturers provide profiled for their paper with factory ink. If you are using 3rd party ink with 3rd party paper you will need to create a color profile. Dyes offer more vivid colors than pigments (typically), but pigments have a longer life (typically).

If you want to get into color management then you need to create a color profile for your camera/lens combination. Calibrate your monitor, and you need a printer that is also profiled and has the color gamut you need.

Why You Should Probably Use sRGB

Most people viewing your images on the web won't have any of this, so sRGB is your best bet for showing the general public.

X-Rite announces new i1Studio end-to-end colour correction system for photographers - DIY Photography
Thanks for this

I should have mentioned my setup...

I work primarily from a fairly-recent 17" HP laptop, sometimes with a consumer-level HP second monitor for editing and reference. Both are colour-calibrated using a ColorMunki Display tool and the relevant software (X-Rite's own for Windows, DisplayCAL for Linux).

I'm not looking to do home printing... my interest - I suppose - is in whether I can reproduce something (very) close to what I see on my calibrated screen via a professional printing service, using their ICC profiles - which, at best (I assume) will be Prophoto RGB compliant.

I'm not concerned with my camera colour profiling (well, I am, but I have that end of things sorted ). My interest begins at the point of editing and export... whether it's possible to reproduce accurately through printing what I see on my calibrated monitors.

Condensing all of that down, I guess what I'm really asking is, can a professional printing service reproduce something very close to what I see on my screen? Do their ICC profiles and printing capabilities cover the same (or wider) gamut of displayable colours? Or is it always going to be a smaller gamut and/or inaccurate compared to what I view during on-screen editing?
10-26-2017, 06:10 PM - 1 Like   #4
Site Supporter
Site Supporter
jatrax's Avatar

Join Date: May 2010
Location: Oregon Cascades
Photos: Gallery | Albums
Posts: 11,656
QuoteOriginally posted by BigMackCam Quote
Condensing all of that down, I guess what I'm really asking is, can a professional printing service reproduce something very close to what I see on my screen? Do their ICC profiles and printing capabilities cover the same (or wider) gamut of displayable colours?
Short answer is yes. Longer answer is this is far more complex than it seems.

First Lightroom (no idea about Darktable) uses ProPhoto RGB internally. However what you see on your screen is your monitor's interpretation of the image using whatever profile you have assigned to it and within the limits of the color rendering of that screen. That can vary widely depending on the type of screen and age. In general consumer laptop screens do not render very closely but they do keep getting better. And sometimes the profile assigned actually oversaturates the actual image to make the colors look stronger than they actually are. That is what the ColorMunki is supposed to fix.

Second, if the image is edited on an accurate color matched screen you should be able to have that printed either on a good quality inkjet or from a pro lab and get quite close. Some colors may run out of gamut on particular images which is what the soft proofing is for. However, soft proofing must use the color profile of the paper, ink and the printer that will be the final output in order to be effective.

Third most pro labs use only sRGB but a few will accept ProPhoto RGB.

Fourth, in the real world, once I had the profile correct and adjusted, I have had little trouble printing either on my printer or at photo labs and getting results that looked very, very close to what was on the screen. I have compared test prints from MPIXPro and Bayphoto and prints from printer to the screen image and felt all were essentially the same.

Fifth, getting accurate printing can be a journey requiring test prints back and forth and a completely color matched work flow.

10-26-2017, 10:43 PM - 1 Like   #5
Pentaxian




Join Date: Feb 2015
Photos: Gallery | Albums
Posts: 4,743
QuoteOriginally posted by BigMackCam Quote
Colour me shocked!... Limitations of screen vs. web vs. printed vs. film colour gamut
Thanks for posting. I've been interested in that topic for awhile. A few things I noticed:
- according to charts, color gamut was wider with film that it is now with digital
- around base ISO (100 to 400 range for full frame or 100-200 range for apsc), color depth doesn't seem to be a limited by the sensors, but it could be limited by the display (print or active display)
- at higher ISO, color depth takes a hit, it degrades much faster than noise and dynamic range (noise and DR are what most people look at on dxo chart, whereas colors starts to degrade much earlier)
- once converted to JPEG for displaying or printing, color is coded with 8bits per channel so there will never be more than 256 tone value, any processing after JPEG conversion will bring less than 8bits of depth per channel, when sharpening is applied to 8bits JPEG, the 8bits quantification noise is magnified how good is camera sensor in that case is irrelevant
- display: most display use 8bits per channel but... graphic card to display interface to be taken care of depending on how many pixels are displayed... The bandwidth of the display interface affect the color resolution. Use a VGA interface to display at HD resolution and fewer gradations of colors will be displayed with banding eventually showing in the image. HDMI is also limited it supports 8bits depth per channel for UHD / 4K (approx. 12M pixels image), only since HMDI version 2.0 (2016). Wide gamut doesn't help, and resolution of the image processing software is not problem.
10-26-2017, 10:47 PM - 1 Like   #6
Pentaxian




Join Date: Jan 2013
Location: Near Vienna, Austria
Photos: Gallery
Posts: 922
I agree with all that jatrax said but want to add a few points.
1. The question of camera calibration is an entirely different one from colour spaces.
2. Using ProPhoto RGB will make your images future-safe but only makes sense in a 16bit workflow. Editing 8bit images in ProPhoto RGB will quickly cause posterization issues (the downside of a wider colour space). Adobe RGB is much narrower than ProPhoto RGB and is a good compromise except when you have really saturated colours in your shots.
3. In that case, the original exposure matters quite a bit. If your saturated colours are clipped internally by the camera even ProPhoto RGB will not get them back.
4. Concerning the link that Winder posted, I agree with the conclusions but its title rather should read "Why You Should Use sRGB If You Don't Care".
10-27-2017, 01:11 PM   #7
Senior Moderator
Loyal Site Supporter
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: Durham, England
Posts: 9,818
Original Poster
QuoteOriginally posted by jatrax Quote
Short answer is yes. Longer answer is this is far more complex than it seems...
QuoteOriginally posted by biz-engineer Quote
Thanks for posting. I've been interested in that topic for awhile...
QuoteOriginally posted by wkraus Quote
I agree with all that jatrax said but want to add a few points...
Thanks, all, for your responses - very helpful and useful info

This has been a major learning point for me - quite surprising, but very interesting.

So, it seems what I see on a calibrated screen when viewing my adjusted RAW images in the software's internal colour-space is the best representation of my image, while web-safe JPEG and printed output is going to be using a much narrower gamut - hence there's the potential for some colour limitations.

I have one more question on this... Can a more-limited gamut such as 8-bit sRGB JPEG affect local contrast?
10-27-2017, 01:34 PM - 1 Like   #8
Pentaxian




Join Date: Feb 2015
Photos: Gallery | Albums
Posts: 4,743
QuoteOriginally posted by BigMackCam Quote
Can a more-limited gamut such as 8-bit sRGB JPEG affect local contrast?
Yes, I think so. That can be improve the look of an image to some extent, or the other way around... currently on my computer I have the same image (taken with K1) displayed with 2 different range of colors. One image pops more, the other image pops less but is more more refined. The image that pops more catch attention first, but when taking more time to look, the more refined image (with slightly larger color space and smoother tone gradation) is simply more beautiful. Anyway, too me it looks like the RAW processing workflow should be tied to the exact media used for the final rendering of the image, including the resolution that should match the display or print size in order not to have the final processing step defined by the media itself.


Last edited by biz-engineer; 10-27-2017 at 01:39 PM.
10-27-2017, 01:45 PM   #9
Senior Moderator
Loyal Site Supporter
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: Durham, England
Posts: 9,818
Original Poster
QuoteOriginally posted by biz-engineer Quote
Yes, I think so. That can be improve the look of an image to some extent, or the other way around... currently on my computer I have the same image (taken with K1) displayed with 2 different range of colors. One image pops more, the other image pops less but is more more refined. The image that pops more catch attention first, but when taking more time to look, the more refined image (with slightly larger color space and smoother tone gradation) is simply more beautiful. Anyway, too me it looks like the RAW processing workflow should be tied to the exact media used for the final rendering of the image, including the resolution that should match the display or print size in order not to have the final processing step defined by the media itself.
Thanks, that makes sense And as for the part I've highlighted in bold above, that's the conclusion I've also come to. Thankfully, Darktable makes it really easy to switch between profiles during editing
10-27-2017, 03:02 PM - 1 Like   #10
Senior Member




Join Date: May 2015
Posts: 255
What software are you using to view the jpg? Is it colour managed? If so are you sure its using the same settings as the raw developer?

My guess is that your jpg viewer isn't colour managed or misconfigured. You can't see more colors during editing if you have a sRGB display.
10-27-2017, 03:08 PM - 1 Like   #11
Site Supporter
Site Supporter
jatrax's Avatar

Join Date: May 2010
Location: Oregon Cascades
Photos: Gallery | Albums
Posts: 11,656
QuoteOriginally posted by BigMackCam Quote
So, it seems what I see on a calibrated screen when viewing my adjusted RAW images in the software's internal colour-space is the best representation of my image, while web-safe JPEG and printed output is going to be using a much narrower gamut - hence there's the potential for some colour limitations.
In general that is correct BUT older laptop screens may actually have less 'in gamut' than printed output, so it is not absolute. Each device (screen, printer whatever) will have a limit on what it can display. The colorspace defines the maximum possible gamut but the device may not always live up to that. I have a two screen setup at my workstation and for several years had two different screens. One a good quality Dell and the other something I picked up at bestbuy on the cheap. Even with both calibrated properly they showed very different images. My wife finally got fed up with my complaining and made me buy another identical Dell.
10-27-2017, 03:16 PM   #12
Senior Moderator
Loyal Site Supporter
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: Durham, England
Posts: 9,818
Original Poster
QuoteOriginally posted by house Quote
What software are you using to view the jpg? Is it colour managed? If so are you sure its using the same settings as the raw developer?

My guess is that your jpg viewer isn't colour managed or misconfigured. You can't see more colors during editing if you have a sRGB display.
I'm using X-Viewer 1.4.3 under Linux Mint 18.2...

However, what I'm seeing in X-Viewer is (to my eyes) identical to what I see when using the soft-proofing tool in Darktable with the output profile set appropriately to sRGB. Both seem to be using the same display profile.

EDIT: Apologies if this makes no sense... I'm still learning about this stuff However... If I set my soft-proofing profile in Darktable to "linear Rec2020 RGB", the soft-proofed image I see looks exactly like the non-soft-proofed, live edited image. When I set the soft-proofing profile to sRGB (web-safe), I see the significant colour differences in heavily saturated areas. If I set soft-proofing profile to "AdobeRGB", it's a *little* better, but still not as good as the Rec2020 profile. That suggests to me that the gamut of colours in sRGB (web-safe) and, indeed, AdobeRGB is less than my monitor can display. Or have I understood this incorrectly?

Last edited by BigMackCam; 10-27-2017 at 03:55 PM.
10-27-2017, 04:32 PM   #13
Site Supporter
Site Supporter




Join Date: May 2016
Photos: Albums
Posts: 1,176
Why would you soft-proof with the Rec2020 profile? Is that relevant to your output device?

Monitor profiles, unless you have a very good monitor, will not necessarily show 100% of the commonly-used color spaces. And the various colorspaces are not necessarily subsets of the other ones, but can represent different colors outside of one of the standard color spaces. Rec. 2020 seems to have a wider gamut than Adobe RGB, but it's hard to say if your display is showing more than Rec. 2020. It may be that your monitor can't actually display all of either of those colorspaces, but what is shows for the Rec. 20202 soft proof is closer matches to what your screen can do. Rec. 2020 is maybe more oriented toward the color space of a video display device, since it is a UHDTV spec, whereas Adobe RGB is not specifically tied to any particular type of device.

From Wikipedia: "In coverage of the CIE 1931 color space the Rec. 2020 color space covers 75.8%, the DCI-P3 digital cinema color space covers 53.6%, the Adobe RGB color space covers 52.1%, and the Rec. 709 color space covers 35.9%."

And "During the development of the Rec. 2020 color space it was decided that it would use real colors, instead of imaginary colors, so that it would be possible to show the Rec. 2020 color space on a display without the need for conversion circuitry."
10-27-2017, 04:41 PM   #14
Senior Moderator
Loyal Site Supporter
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: Durham, England
Posts: 9,818
Original Poster
QuoteOriginally posted by leekil Quote
Why would you soft-proof with the Rec2020 profile? Is that relevant to your output device?
My point here is that by using that output profile in soft-proofing, I see exactly what I see when editing my RAW image in Darktable. If I set soft-proof to sRGB (or AdobeRGB for that matter), I see significant impact on highly-saturated colours, and in fact I see those affected areas highlighted when I select the gamut checking option.

Clearly, what I'm seeing during live editing is much richer and more saturated in some areas than the soft-proofed and exported files using the sRGB output profile.
10-27-2017, 04:48 PM - 1 Like   #15
Pentaxian




Join Date: May 2016
Photos: Albums
Posts: 1,864
I have the same issue. I've just worked on few files I took this fall, exported under ProPhoto profile to Photoshop, worked on the image there, and exported a jpeg. Yellows are way less vivid, and frankly images lost a lot of the magic of the season. I wasn't able to find a way to make them as vivid and vibrant as in ProPhoto mode. Haven't tried printing those files yet. Is it possible to print from ProPhoto? Or it has to be converted to sRGB? I'm also working on a laptop (100% rgb coverage) calibrated with ColorMunki.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
colour, colours, film, gamut, lightroom, output, photography, photoshop, profile, screen, vs, yellows
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Gamut Stand Up tgchan Monthly Photo Contests 2 10-09-2016 12:19 PM
I'm Shocked Part 2: Solyndra mikemike General Talk 12 09-19-2011 02:59 PM
I'm Shocked gokenin General Talk 135 09-16-2011 07:02 AM
Twice shocked........... John Kovarik Pentax SLR Lens Discussion 3 04-17-2008 01:03 PM
Nikon D40X - I was shocked! magnum1 Pentax DSLR Discussion 52 01-01-2008 08:31 AM



All times are GMT -7. The time now is 10:32 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top