Sir Earl,

Do you have a workflow for ProphotoRGB? What is the correct histogram or any relevant information in order to decide whether to convert Raw into SRGB, ARGB or Prophoto? Also, what is the difference between assigning a profile (color space) and converting a profile?

Of course, I shoot in ARGB. Thanks for the reply in advance.

Sir Earl,

Do you have a workflow for ProphotoRGB? What is the correct histogram or any relevant information in order to decide whether to convert Raw into SRGB, ARGB or Prophoto? Also, what is the difference between assigning a profile (color space) and converting a profile?

Of course, I shoot in ARGB. Thanks for the reply in advance.

My question to you ern is that why work in Prophoto?

I started a new thread to your question which should be on its own since it deals with a different topic.

Assigning a Profile preserves the numbers of the file. It takes those numbers and "assigns" them to another color space. This will change the color of your image because the numbers have different meanings in different color spaces.

Convert to Profile preserves the colors of the image while changing the numbers. If you convert your image to different color spaces, the color should remain the same so long as the gamut of the new space matches the gamut of the old space and so long as your image lies within the same gamut of both spaces.

Convert to Profile is the root of color management. Its how you can have your file in a space like Adobe RGB and reproduce the same color across different devices and output machines.

We prefer using Adobe RGB at our studio since it offers a wider gamut than sRGB. Many professionals use Prophoto but sometimes this space is too wide for many output machines and may be overkill at the moment.

My question to you ern is that why work in Prophoto?

Since we are using Photoshop ACR to convert Raw, why dont we take it's full advantage of preserving all or most of the colors of what the camera sensor has actually saw/captured by converting to ProphotoRGB instead of ARGB and SRGB. By the wider gamut of Prophoto, we can store files/images that in the future can give us a better result than ARGB and much more from SRGB. Technology is very fast and monitors will not remain forever in SRGB mode. Printers/output machines are also catching on in these color spaces.

Look at this way, we use to convert to 16 bit mode for better control in post processing yet the end result will be an 8 bit SRGB in jpeg. So, why not start from a wider gamut like ProphotoRGB.

Anyway, my real question is what will be the determining factor in choosing the color space when you are in Photoshop ACR? Is it by simply checking the histogram for clipped highlights and shadow by which Prophoto or ARGB will show a lesser or no clipped highlights/shadow?

I started a new thread to your question which should be on its own since it deals with a different topic.

We prefer using Adobe RGB at our studio since it offers a wider gamut than sRGB. Many professionals use Prophoto but sometimes this space is too wide for many output machines and may be overkill at the moment.

Thank you sir. I know that your reply is the prevailing logical reason why ARGB is still a better approach in color space when you are shooting in ARGB mode.

The gamut of ProPhotoRGB is really so large that there's a need to control or contend with banding and other artifact problems, even when you are in 16-bit mode. However, I am really attracted to Prophoto and really like to take some tips/workflow in using this color space.

Anyway, my real question is what will be the determining factor in choosing the color space when you are in Photoshop ACR? Is it by simply checking the histogram for clipped highlights and shadow by which Prophoto or ARGB will show a lesser or no clipped highlights/shadow?

Often, we complicate simple things. Use your eyes and mind, then you will know. Ohmmmmmmm......~~~~ :D

Of course, you can tell the difference. Open a raw file (images in landscape is a better example) in Adobe Camera Raw and turn on the highlight clipping options (in CS3 beta - its at the top, just check preview, shadows, highlights) and try the 3 color spaces one at a time - aRGB, sRGB, ProphotoRGB. The bright reds will show the portion in each where the clipping would occur. And most of the time for most images, sRGB always loses out (have more clipping) than aRGB while ProphotoRGB able to encompass the color without clipping (if there's clipping it is lesser than aRGB).

This is one of the determining factor that I know of that's why I'm asking if there are other factors to consider.

Digital photography is a very complicated matter. Have you ever wonder why digital camera sensor is a linear device, yet we use a non-linear CRT monitor to see or edit the images and as a result we need to calibrate our monitor? It's simply because we have no choice but if we have the option it will be different. It's in the same way that we are presented with different color spaces so the choice is in our hand, never mind about LAB color, Color Match, etc. - I guess just for now.

Of course, you can tell the difference. Open a raw file (images in landscape is a better example) in Adobe Camera Raw and turn on the highlight clipping options (in CS3 beta - its at the top, just check preview, shadows, highlights) and try the 3 color spaces one at a time - aRGB, sRGB, ProphotoRGB. The bright reds will show the portion in each where the clipping would occur. And most of the time for most images, sRGB always loses out (have more clipping) than aRGB while ProphotoRGB able to encompass the color without clipping (if there's clipping it is lesser than aRGB).

You can take my word that I have been where you are now. Read again what I have written earlier and give it some thought.

At the end of the day, you will present/be presented an image...not a histogram.:)

You can take my word that I have been where you are now. Read again what I have written earlier and give it some thought.

At the end of the day, you will present/be presented an image...not a histogram.:)

Thank you very much for the info Sir. Anyway, my OP is about workflow in using ProphotoRGB and not a debate on the benefit of using ProphotoRGB. I have my workflow in using ProphotoRGB and if anyone interested, I can post the details here. This is just the main summary which is starting from shooting aRGB mode, converting Raw file using ACR into 16-bit mode Tiff for further post processing inside CS2, then using LAB Color for USM and then converting to sRGB depending in the output whether for web or printing.

Converting back to sRGB is the reason why I ask the difference between assigning and converting profile (which is clearly explain by Sir Nick as that is also my presumption). Also, for what it's worth - I'm just a hobbyist.

I guess for now, I have to march with a different drummer, thank you.

No taker for my ProphotoRGB workflow?

I posted some pics which are PP (post processed) through ProphotoRGB in Photoshop ACR. The clipped highlights (before PP) are easily managed. I must admit I'm not good in obtaining correct exposure so I always depend on raw conversion (thanks that cameras allow us to shoot raw+jpeg). Discard PP if the jpeg is as close as it can to a correct/acceptable exposure. And yes, there's the benefit of shooting Raw, much more in aRGB mode.

The posted pics are in Desert Fox Romancing Arabian Horses...my very first in posting here and my very first in joining group hug.

When you process an image in ProphotoRGB or ARGB colorspace, you can either "assign" the sRGB color profile or "converted" to the sRGB color profile. To make a Prophoto or ARGB encoded image into an sRGB image, you must use the "convert" function but not the "assign" function. The "convert" function will actually change the color values in the file so that the output will display the same color when interpreted with the sRGB profile. And this is what it should be.

The "assign" function will merely change the label on the file to sRGB and will not fix the colors. Therefore it will make the image look washed-out in all applications both color-managed and non-color managed or in web browser i.e. Internet Explorer, Firefox, etc. The ONLY time you should use the "assign" function is when an image is wrongly labeled that you need to fix the label and assign the proper label for it's color encoding. So, this is only needed if an image has previously been assigned the wrong label.

EDIT---CONVERT TO PROFILE----Profile:sRGBIEC61966-2.1 (Destination Space)

Conversion options- Engine: Adobe (ACE), Intent:Relative Colorimetric

checkmark Use Blackpoint Compensation

In Lightroom version 1, it is highly recommended to use 16-bit ProphotoRGB because this colorspace encompasses most colors that cameras can record.

And I quote: 16-bit ProphotoRGB is the recommended choice for best preserving color details from Lightroom

"You may say I'm a dreamer, but I'm not the only one
I hope somebody you'll join us and the world will be as one" - John Lennon's Imagine

THere's a convert and assign?
So converting from sRGB to aRGB shouldn't cause color shift right? (bec of the smaller gamut)
Where as assigning a profile causes color shifts!

All this time i thought i was converting profiles when in fact i'm assigning.

Sometimes I really like the results of assinging profiles.
Assinging aRGB to an sRGB file looks like a color boost! Funky!

Converting causes a change in the RGB values or color numbers due to a change in scale.

Assigning does not change the RGB values or the color numbers, but it does change the scale.

ok, got it!
thanks for clearing that up

I tried it
visually, not numerically, assigning profile is the one that changed and made a color boost. Converting didn't change the colors visually.

That's because the numbers mean different things depending on which color space you use.

The numbers don't make any sense if they don't refer to a specific color space.

A RGB value of R=230 G= 98 B=122 represents different colors in Adobe RGB and sRGB :D