Prophoto to sRGB conversion technique

SusanB

Hi ,

I do not know why smugmug's conversion of my image from prophoto to sRGB looks excellent, while my conversion in PS CS3 looks really washed out and anemic even after increasing the saturation a lot.

Here are the links to view my dilemma:

I uploaded the prophoto color space to smugmug, not knowing they were still in prophoto and smugmug changed them to sRGB and they looked no different to me:

http://susanb.smugmug.com/gallery/5298762_9FLW6/1/323220172_QdhSd/Large

Then, I took the prophoto image and changed it to sRGB in PS CS3 and uploaded it to smumug and it is really ugly:

http://susanb.smugmug.com/gallery/5298762_9FLW6/1/323339034_E93NN/Large

What am I doing wrong to ruin the images? :confused

Anyone have any idea?

The way that I realized the original color space was prophoto was when I uploaded the image to another website and it looked horribly washed out and anemic. :cry

Thanks ahead of time,

Susan

jfriend

SusanB wrote:

Hi ,

I do not know why smugmug's conversion of my image from prophoto to sRGB looks excellent, while my conversion in PS CS3 looks really washed out and anemic even after increasing the saturation a lot.

Here are the links to view my dilemma:

I uploaded the prophoto color space to smugmug, not knowing they were still in prophoto and smugmug changed them to sRGB and they looked no different to me:

http://susanb.smugmug.com/gallery/5298762_9FLW6/1/323220172_QdhSd/Large

Then, I took the prophoto image and changed it to sRGB in PS CS3 and uploaded it to smumug and it is really ugly:

http://susanb.smugmug.com/gallery/5298762_9FLW6/1/323339034_E93NN/Large

What am I doing wrong to ruin the images? :confused

Anyone have any idea?

The way that I realized the original color space was prophoto was when I uploaded the image to another website and it looked horribly washed out and anemic. :cry

Thanks ahead of time,

Susan

The secret is in how you convert it to sRGB. In CS3, you should use Edit/Convert to Profile/sRGB. If you do that, all colors from your image that fit in the sRGB colorspace (which will be most if not all of them), will stay exactly the same.

Do not use Edit/Assign Profile. That will give you washed out results.

After "converting to the right profile, your image will be in sRGB and when you save it, that sRGB profile should stay with the image and colors will be preserved.

SusanB

jfriend wrote:

The secret is in how you convert it to sRGB. In CS3, you should use Edit/Convert to Profile/sRGB. If you do that, all colors from your image that fit in the sRGB colorspace (which will be most if not all of them), will stay exactly the same.

Do not use Edit/Assign Profile. That will give you washed out results.

At this point, you image is now in sRGB and when you save it, that sRGB profile should stay with the image.

jfriend,

Thanks so much! With my lack of sleep I did not notice the subtleties. You have solved the problem and made me a very happy camper

Susan

BinaryFx

It is amazing how many get caught by this!

A Google search for "difference between assign profile & convert to profile" will bring up many results, such as:

http://www.colormanagementinfo.com/page1/page10/page10.html

http://www.adobeforums.com/webx/.3bc6b157

Stephen Marsh
http://members.ozemail.com.au/~binaryfx

arodney

http://www.ppmag.com/reviews/200407_rodneycm.pdf

Rhuarc

Does anyone know how this works with regards to LR? I use LR as my RAW converter, then after I export the changes to xmp files I convert all the files to DNG and import into IDImager. Are the DNG files then using the ProPhoto?

jfriend

Rhuarc wrote:

Does anyone know how this works with regards to LR? I use LR as my RAW converter, then after I export the changes to xmp files I convert all the files to DNG and import into IDImager. Are the DNG files then using the ProPhoto?

Do you know how IDImager previews the DNG files? My guess would be that it just shows you the preview embedded in the DNG file. If my reading of the DNG specification is right, the DNG file itself contains a marker for the colorspace of the preview image and the program rendering the preview image is then supposed to pay attention to that colorspace when rendering the preview.

I can't find it written anywhere what Lightroom uses for the colorspace of the previews that it creates. The two logical guesses would be ProPhotoRGB (since that's what LR uses internally to render) and sRGB (because that might be easier for programs looking at the preview image to display).

arodney

Rhuarc wrote:

Does anyone know how this works with regards to LR? I use LR as my RAW converter, then after I export the changes to xmp files I convert all the files to DNG and import into IDImager. Are the DNG files then using the ProPhoto?

All processing in LR and ACR are done in high bit, ProPhoto RGB (with a linear tone curve):

http://www.ppmag.com/reviews/200701_rodneycm.pdf

The embedded JPEG in the DNG is in sRGB.