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ukbrown 05-22-2006 07:46 PM

Colour space in camera advice needed
 
What is the perceived wisdom for colour space in your camera.

1. Pick Adobe 1998 because it has a larger gamut than srgb. Leave all your
photos in and any you upload to be printed convert to srgb
2. Leave the camera in srgb

Will photos in Adobe 1998 format look any different once uploaded to my web
pages or should they be converted to srgb.

The main reasons for using Adobe seem to be that this is what most inkjet
printers print with. I do not do that much printing but noticed that the
colour space was a bit broader. If I shoot in Raw I take it that in
Photoshop I should be using Adobe 1998. My Canon camera manual recommends
not using Adobe, hence my confusion.

Any good beginners articles on what seems to be an incredibly detailed area
welcome. I am quite happy to go away and read.

Thanks
Ukbrown

Bill Hilton 05-22-2006 08:18 PM

Re: Colour space in camera advice needed
 
>ukbrown writes ...
>
>What is the perceived wisdom for colour space in your camera


Shoot RAW mode and the color space defined in-camera is ignored. You
assign a space when you convert the RAW file later.

If shooting jpeg then it's a personal choice, sRGB for web images,
AdobeRGB for print images is common but many shoot AdobeRGB and convert
the profile later for web files, and many shoot sRGB and print them, so
it's a matter of choice.

>Will photos in Adobe 1998 format look any different once uploaded
>to my web pages or should they be converted to srgb.


You should convert to sRGB first because the same color has a different
numerical value in sRGB vs AdobeRGB and saturated colors look dull if
not converted. This is because the web browsers don't use the ICM
color management flow so ignore the profiles and sRGB values are closer
to what the web browser will display.

If you want to see an example here is a cardinal with very red colors
converted from RAW into three working spaces, wide gamut ProPhotoRGB,
AdobeRGB and sRGB. These were saved as jpegs without converting the
ProPhoto or AdobeRGB files to sRGB first.

The "red" of the feathers is represented roughly by 144/86/46 in
ProPhoto, 200/77/39 in sRGB and 158/53/0 in AdobeRGB ... a
color-managed program like Photoshop will read the profile tag and show
roughly the same colors but a non-color managed app like your web
browser will simply ignore profiles and see these as very different
colors. Download these and assign the correct profiles in Photoshop
and you'll see they look similar. Convert the ProPhoto or AdobeRGB
images to sRGB and they will look similar on the web. Don't convert
and they look terrible.
http://members.aol.com/bhilton665/hilton_adobergb.jpg
http://members.aol.com/bhilton665/hilton_srgb.jpg
http://members.aol.com/bhilton665/hilton_prophoto.jpg

Bill


Daniel Silevitch 05-22-2006 08:46 PM

Re: Colour space in camera advice needed
 
On 22 May 2006 13:18:47 -0700, Bill Hilton <bhilton665@aol.com> wrote:
>
> You should convert to sRGB first because the same color has a different
> numerical value in sRGB vs AdobeRGB and saturated colors look dull if
> not converted. This is because the web browsers don't use the ICM
> color management flow so ignore the profiles and sRGB values are closer
> to what the web browser will display.


Nitpick: I believe that recent versions of Safari on the Mac do
understand color space information, at least to some extent.

-dms


Bill Hilton 05-22-2006 10:10 PM

Re: Colour space in camera advice needed
 
> Daniel Silevitch writes ...
>
>Nitpick: I believe that recent versions of Safari on the Mac do
>understand color space information, at least to some extent


For several years a few browsers have been "color managed" but there
are two problems ... very few people use those browsers, and most jpegs
for the web have the tags stripped out to save a few bytes, so the
profile info isn't available in most images anyway ...

Bill


Daniel Silevitch 05-22-2006 11:02 PM

Re: Colour space in camera advice needed
 
On 22 May 2006 15:10:36 -0700, Bill Hilton <bhilton665@aol.com> wrote:
>> Daniel Silevitch writes ...
>>
>>Nitpick: I believe that recent versions of Safari on the Mac do
>>understand color space information, at least to some extent

>
> For several years a few browsers have been "color managed" but there
> are two problems ... very few people use those browsers, and most jpegs
> for the web have the tags stripped out to save a few bytes, so the
> profile info isn't available in most images anyway ...


Well, there is that.

Did the test jpgs that you posted have embedded profiles? When I looked
at them in Safari 2.0, they were visibly quite different from each
other, especially the ProPhoto one.

-dms

Bill Hilton 05-22-2006 11:19 PM

Re: Colour space in camera advice needed
 
> Daniel Silevitch writes ...
>
>Did the test jpgs that you posted have embedded profiles?


No. I used Photoshop's 'save for web' and the default is to strip out
the ICC profiles, though there's an option to leave them in. I think
AdobeRGB adds around 500 bytes, ProPhotoRGB around 1,000 bytes and sRGB
almost 4,000 bytes to *each* image, so that's why they are stripped out
by default.

> When I looked at them in Safari 2.0, they were visibly quite
> different from each other, especially the ProPhoto one.


If they did have profiles and you were using a color managed browser
then they would look very similar, which you can show by downloading,
opening in Photoshop and assigning the right profile (if you have the
missing/mismatch warning set it will prompt you automatically).

Bill


Daniel Silevitch 05-23-2006 03:12 AM

Re: Colour space in camera advice needed
 
On 22 May 2006 16:19:06 -0700, Bill Hilton <bhilton665@aol.com> wrote:
>> Daniel Silevitch writes ...
>>
>>Did the test jpgs that you posted have embedded profiles?

>
> No. I used Photoshop's 'save for web' and the default is to strip out
> the ICC profiles, though there's an option to leave them in. I think
> AdobeRGB adds around 500 bytes, ProPhotoRGB around 1,000 bytes and sRGB
> almost 4,000 bytes to *each* image, so that's why they are stripped out
> by default.


That's what I thought, because I've seen examples of jpgs with embedded
profiles, and Safari gave similar-looking images for the different
spaces, whereas Firefox gave very different looks.

I'm mildly startled that Firefox doesn't support color management; I
wonder whether it's on the to-do list.

>> When I looked at them in Safari 2.0, they were visibly quite
>> different from each other, especially the ProPhoto one.

>
> If they did have profiles and you were using a color managed browser
> then they would look very similar, which you can show by downloading,
> opening in Photoshop and assigning the right profile (if you have the
> missing/mismatch warning set it will prompt you automatically).


I don't have Photoshop, but I'll take your word for it.

-dms

ukbrown 05-23-2006 06:19 AM

Re: Colour space in camera advice needed
 

On 22-May-2006, "Bill Hilton" <bhilton665@aol.com> wrote:

> If shooting jpeg then it's a personal choice, sRGB for web images,
> AdobeRGB


So basically I should not be worried about the differnece in colour space
size.

Thanks for the detailed reply.

Raphael Bustin 05-23-2006 11:39 AM

Re: Colour space in camera advice needed
 
On 22 May 2006 15:10:36 -0700, "Bill Hilton" <bhilton665@aol.com>
wrote:

>> Daniel Silevitch writes ...
>>
>>Nitpick: I believe that recent versions of Safari on the Mac do
>>understand color space information, at least to some extent

>
>For several years a few browsers have been "color managed" but there
>are two problems ... very few people use those browsers, and most jpegs
>for the web have the tags stripped out to save a few bytes, so the
>profile info isn't available in most images anyway ...
>
>Bill



If I read the notes correctly, Firefox (PC and Mac) are both
ICC-aware as is Internet Explorer on the Mac.


rafe b
www.terrapinphoto.com


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