I've been trying ProPhoto RGB should I add a convert to sRGB to my export action

[earlybird]

Hi,
 I have been learning how to transition from a sRGB Photoshop processing workflow to a ProPhoto RGB Photoshop environment.

 In the short term I have been exporting jpegs using the "save to web" Image Ready routine which is where I convert to sRGB colorspace and embed the sRGB tag.

 Now I would like to address the need to convert from ProPhoto RGB to sRGB with the "actions" that I already use for batch or automated conversion. I usually collect "master" flattened .tif files in a directory and run a batch to save as jpeg files.

 I plan to add a convert to sRGb step in the actions but it occurs to me that I will be dealing with a legacy of existing sRGB masters for a long time so I am wondering what the ramifications of having a collection of master files that are a mix of sRGB and ProPhoto RGB and running one action on them. Is there a gotcha associated with running a convert to sRGB command on a file that is already sRGB?

 Thank you.

[digitaldog]

Is there a gotcha associated with running a convert to sRGB command on a file that is already sRGB?

Shouldn't be, it will basically be a 'null' conversion. From a JPEG, there could be more rounding errors, data loss due to the JPEG format resave. I'd be more concerned with that to a tiny degree than two sRGB conversions.

[earlybird]

Thank you for the information Andrew.

I'll never go from jpeg to jpeg. My workflow is .CR2 > multilayer .psd or .psb > flattened .tif collections > sRGB jpeg collections.

I end up collecting the flattened .tif in directories that represent themes. For example "Yellowstone 2015". This way I can have a small collection of keepers that I can access very quickly, while also preserving access to the multi layer files in a more cumbersome and exhaustive archive.

Thank you.

[bjanes]

Hi,
 I have been learning how to transition from a sRGB Photoshop processing workflow to a ProPhoto RGB Photoshop environment.

 In the short term I have been exporting jpegs using the "save to web" Image Ready routine which is where I convert to sRGB colorspace and embed the sRGB tag.

You might want to look at the sRGB v4 Preference profile, but its use is unclear to me. In the example on the ICC web site, one starts out with a ver 2 sRGB profile, assigns it to the ver 4 sRGB profile and then prints using a ver 4 printer profile, using the desired rendering intent. This is covered in the ICC White Paper 26 document, but the whole process does not make sense to me.

The problem is that I don't have any ver 4 printer profiles. Normally if one is going from a wider to narrower space, such as ProPhotoRGB to printer, one uses the printer profile to do the gamut mapping, not the source profile.

To add to the confusion, there is also a sRGB Appearance Profile, which is covered in White Paper 42

Expert comments are welcomed.

Bill

[digitaldog]

Experimenting with a V4 sRGB profile would certainly be a good idea, can't hurt. But what it provides is a Perceptual table and that would suggest one soft proof that and RelCol and decide on an image by image basis which to use. Also not sure what Save for Web will select or if there's an option for an RI.

[earlybird]

You might want to look at the sRGB v4 Preference profile...

Hi Bill,
 Thank you for the heads up. I don't have printing equipment and have been relying on a couple service providers that have limited choices. Working in ProPhoto RGB may cause me to seek out more flexible printing solutions in the future. I haven't been unhappy using a Raw to sRGB work flow but have seen so many compelling explanations about using ProPhoto in Photoshop that I thought I should evolve towards using it.

[bjanes]

Experimenting with a V4 sRGB profile would certainly be a good idea, can't hurt. But what it provides is a Perceptual table and that would suggest one soft proof that and RelCol and decide on an image by image basis which to use. Also not sure what Save for Web will select or if there's an option for an RI.

Andrew,

If I have a wide gamut image (say a colorful red flower) rendered into ProPhotoRGB from my digital camera, how does one make use of the V4 sRGB profile? The ver 2 ProPhotoRGB profile lacks perceptual rendering tables so one could not convert to sRGB using perceptual rendering via the ProPhoto profile. Does the ver 4 sRGB allow perceptual rendering into sRGB using a ProPhoto source?

Thanks,

Bill

[Tim Lookingbill]

Unless they've changed things in this V4 sRGB from when I tried it out years ago and demonstrated what it does to a ProPhotoRGB preview upon converting all it does is lift the shadows a bit just like a perceptual effect when soft proofing for printing with a printer profile except the V4 sRGB space shows a bit more shadow defintion.

And it doesn't apply this shadow lift enough to alter saturated colors like a flower. It's too subtle on most images I've converted to that I don't even bother using it.

[digitaldog]

Does the ver 4 sRGB allow perceptual rendering into sRGB using a ProPhoto source?

Exactly, there should be a Perceptual table you can try, keeping in mind all perpetual renderings can vary.

[Redcrown]

Nobody has mentioned bit depth yet. Most experts agree that you should stay in 16 bit mode when using ProPhoto. All agree that editing a ProPhoto image in 8 bit is a bad idea and can often cause banding. But some also claim that simply converting a finished ProPhoto image from 16 bit to 8 bit can also cause banding. I've seen demos of that, although they were based on extraordinary images with gamuts and gradients that were prone to banding.

So, when you go from 16 bit ProPhoto to 8 bit sRGB (for jpeg), be careful when the bit depth conversion occurs. To be safe, it should occur after the colorspace conversion so that it happens in sRGB and not ProPhoto.

Does anybody know how "save for web" works. Which does it do first, colorspace conversion or bit depth conversion?