Save 15% On Excire Foto Software With Code: EXCIRE-EP

sRGB and Soft-Proof Monitor


philwig 16 817 1
17 Jun 2005 12:30AM

Quote:When you save for web PS doesn't use a rendering intent, instead it uses 'preserve colour numbers'. To correctly soft proof what it will look like select srgb & tick the 'preserve colour numbers' box - should give an accurate proof.


Can you tell me what makes you think that this is so? I can't find a specific reference in PS/CS2 help, but the implication is that the colour preferences rendering intent is used everywhere that colour conversions are required except for the proofing settings, which are independent. Is there somewhere else (other than colour preferences and proof settings) that you can tweak this?


--
That makes me think...

Then you try to simulate sRGB in "save for web". You want the picture to look the same there to the way it looks if you convert the image to sRGB. I think this is your goal.

If it looks different, the only reason I can see would be that the rendering intent is different for proof than color preferences - can you check that?

Note that from what I remember, you have to set colour preferences and the proof set up with no document actually open or they apply to the open document only. So set them and check them, then have a go.
mattmatic 17 598
17 Jun 2005 3:31AM
Chris,

Quote:So I wonder if its your working colour space that is causing the problems?


Well, as I said, it's not a problem on the other machines.

Phil - thanks for the comments. I'll double check the rendering intents, and go through the whole colour setup of PS-CS.

I'll let you know what happens.

Appreciate everyone's help on this Wink
Matt
brm 17 76
17 Jun 2005 9:01AM
Right, think I've found the problem and the solution (hopefully!).

I was sort of wrong & kind of right with what I said about how PS converts the colours when you save for web..

If you are in a different colour space, e.g. Adobe 1998 etc, then I'm 99% sure that PS uses 'preserve colour numbers' when it converts it to srgb - I can't find anything definate on the web about this, but there're no settings that I can find in PS to change.

However...

If you go to image > mode > convert to profile and select srgIEC61966-2.1 then pick your rendering intent & apply it then your image *should* look exactly the same when you save for web as it's already in the correct colour space & doesn't need to be converted.

Does that make sense? Let's hope so 'cause it's Friday afternoon and I'm now off home.... hurrah!

b
mattmatic 17 598
18 Jun 2005 3:15AM
Hi B,

Yes, your reply makes perfect sense. You are right that SFW uses Preserve Color Numbers.
However, I have converted to sRGB, and I have Spyder'd the monitor to sRGB, and yes still it doesn't look the same!
There must be some wretched hidden profile cutting in somewhere that's messing everything up.

A calibrated monitor (let's say calibrated to D65, gamma 2.2) should take an RGB value and display the same colour for that value on any other monitor that's been calibrated the same (well, near enough). What I'm finding is that for some peculiar reason this isn't happening.

OptiCAL lets you compare with and without the applied profile. Without the dialog box grays are very blue (in fact the blue response is a bit too eager). With the profile enabled, I get completely neutral grays. And, for example, the EC set on here looks absolutely fab.
Yet, if I copied an image from the web, paste into PS and assign (not convert) the profile sRGB then I get an oversaturated image. It's like the gamut of the web/monitor is narrower than what PS is seeing as sRGB (perhaps also with a white point change).

I just can't quite get my head round where the problem is. OptiCAL displays a graph of the resultant calibration, and it looks pretty good to me, certainly better than the uncalibrated graph. Yet there's still this mismatch between the browser view and PS's sRGB.

The only benefit of all this pain is that it's making me think a lot harder about what exactly is going on underneath with colour management :o)

I have checked all the colour settings, with and without a document loaded, and it matches the desktop settings. And, as I'd expect, when converting between colour spaces the results are the same (i.e. converting from AdobeRGB to sRGB in PS shows practically no change, in PS.)

The odd thing is that it's only on this PC that I've seen this happen so drastically. My older Dell laptop used to behave similarly and I never quite understood why my uploaded images would appear darker when I'd edited on the Dell. Maybe I had the same problem, but not so acute.

Matt
philwig 16 817 1
18 Jun 2005 3:52AM
I think you need to try to get it down to a simple thing, so you can debug it.


Quote:Yet, if I copied an image from the web, paste into PS and assign (not convert) the profile sRGB then I get an oversaturated image.


So that's just wrong, hence it may be a simple place to fix the issue.

If your working space is Adobe RGB.. save an image from the web on your desktop. Open it, assigning sRGB and converting to Adobe RGB as you do so. The image looks precisely the same in PS as it does in IE. Repeat and assign an incorrect profile and it looks wrong.

Note that this should work irrespective of how screwed up your monitor profile is (or not) because all the images are being viewed on the same monitor, through the same profile. I can't say that you'll see the "correct" colours, but they should at least be consistent.

If that doesn't work, I'd zap your PS config and run with the default, because the defaults will work as I have described.
mattmatic 17 598
20 Jun 2005 1:22AM
Phil,
That's exactly what's happening - and it shouldn't! Photoshop has got some other profile or setting that's messing up the on-screen display. A saved image views the same in IE/Firefox as it does in Irfanview.
Load it into PS and assign it sRGB - zphlat. Colours wrong.

Just going digging for all the Photoshop settings, including Adobe Gamma (that may have something else to do with it, I don't know). I'll let you know when I've found the offending part!

Matt
mattmatic 17 598
20 Jun 2005 1:44AM
Well, I've wiped the "Color Settings.csf" and the "Adobe Photoshop CS Prefs.psp" files, rebuilt the information (Europe Prepress Defaults).

It's still exactly the same as before :-(

Going mad now....
Matt
lobsterboy Plus
17 15.0k 13 United Kingdom
20 Jun 2005 1:57AM
Do you have adobe Gamma running in your startup? Does disabling it make any difference?

Other than that it looks like we are running out of software to blame Sad
mattmatic 17 598
20 Jun 2005 2:13AM
I disabled Adobe Gamma loooong ago Wink
But I'll double check...
brian1208 18 11.8k 12 United Kingdom
20 Jun 2005 2:40AM
Chris - thanks for the reminder about disabling Adobe Gamma. I've recently started seeing a magenta tint coming into my screen which meant that I wasn't able to get my screen : printer : photobox colour card to match.

I checked, Adobe Gamma had switched itself back on at some point during various recent downloads. Switched it back off - everything now matches Smile

Brian
mattmatic 17 598
20 Jun 2005 5:53AM
Ok, ready to cook your noodle?!

A loaded sRGB image only looks the same under either of the following conditions:
1) Colour management is set to "Off"
2) I soft proof to the "Monitor" profile

Of course, option 1 is effectively the same as 2, since choosing the option "Color Management Off" selects the monitor profile.

Erm. So, what am I actually looking at when not soft proofing??!

I have double, triple, quadruple checked that Adobe Gamma is not loading, and that there's nothing else loading on startup except the OptiCAL loader (which is just checking whether the profile has changed, since during the Spyder calibration phase it generates an ICC file that is correctly showing in the color management section of the display properties).

Still completely and utterly stumped by this :-|
Matt
mattmatic 17 598
20 Jun 2005 8:57AM
Ok. This is one of those DOH! moments Smile

Went to Display Properties, to the Advanced button, and to the Color Management tab. Now I thought there should the profile of the calibrated monitor in there.

Wrong.

Removed the profile, so there's nothing associated with my display adaptor at all. Double checked that OptiCAL was doing its job (it appears to be, though I haven't done an exhaustive check), run up Photoshop and the colours match the web when in sRGB mode!!

Either that or I have absolutely no colour management at all now... any explanations???!!

Matt

Sign In

You must be a member to leave a comment.

ePHOTOzine, the web's friendliest photography community.

Join For Free

Upload photos, chat with photographers, win prizes and much more.