Print module Editing in ProPhoto RGB vs sRGB

[theferret]

Lightroom Version Number

14.3

Operating System

1. Windows 11

Hi

Hoping someone here can clarify some issues I am having with printing. My understanding is that sRGB is used for exporting to Web and printing as it is the most common colour space, but ProPhotoRGB is the widest gamut with most colours. I accidentally exported an image to PS using the default ProPhotoRGB, and then sent that TIFF, with ProPhoto RGB colour space embedded, to a professional printer. The image came back completely washed out. When I converted the profile to sRGB in PS in looked the same on screen and printed fine.

My question is why use ProPhotoRGB for anything if at the end of the day you need to convert to sRGB to make use of the image? If I change my preference in LR for editing in PS or other external application, to sRGB, instead of default ProPhotoRGB, what am I losing out on? Just seems I creating work and room for error creating ProRGB TIFF that must be converted to sRGB.

Thanks for any education as never printed stuff before so whole new ball game.

Mike

 

[clee01l]

My question is why use ProPhotoRGB for anything if at the end of the day you need to convert to sRGB to make use of the image? If I change my preference in LR for editing in PS or other external application, to sRGB, instead of default ProPhotoRGB, what am I losing out on? Just seems I creating work and room for error creating ProRGB TIFF that must be converted to sRGB.

ProPhotoRGB is a computational color space. Mathematical operations in a program like Lightroom and photoshop can generate pixel color values outside of the visible spectrum as seen in the accompanying chart. sRGB has the smallest envelop. Old CRT monitors could barely produce colors to fit inside that envelop. Printers then and now could reasonably produce colors that fit inside the AdobeRGB envelop. The movie industry adopted the DCI-P3 standard for displaying projected images. Kodak established ProPhotoRGB as a color standard. When you create an image file, you map the pixel in the image data to an icc profile that fits inside one of these envelopes. So if a calculated pixel color falls inside ProPhotoRGB but outside of sRGB, an image file that is using sRGB will remap those colors to fit inside the sRGB envelop. So which color profile should you use for the file that you create?

Ideally, a quality 3rd party print company will generate and specify icc profiles to match the color capabilities of the print hardware AND paper being used. This would insure that all of the pixel colors in the image file fall inside a colorspace that the print hardware and paper is capable of producing.

If a print company specifies that you use sRGB, it is because they have chosen the least common denominator for all of the images sent to them. Hopefully they have tuned their equipment to match the characteristics of sRGB. If you do your own printing at home you should create image file to match an icc profile supplied by the paper manufacturer.

Why sRGB? It is an old standard. You can be sure that this envelop will be inside what ever device/media you use to view your image. Cameras default to sRGB for the JPEGs they produce. AdobeRGB is often an option for JPEGs produced by the camera. Only if you shoot RAW in camera where the color space is not defined can you get a larger color space envelop to process with.

Lightroom Classic and PhotoShop process using a variation of ProPhotoRGB that they call MelissaRGB after the person that developed it at Adobe. Again it is for computation not for viewing. Pixels sent from an Adobe product to the monitor will be mapped to the monitor color characteristics. You use these in Windows to make sure that the color pixel that will map inside the envelop of the monitor. Today's modern LED monitors have HDR capability and usually are advertised as AdobeRGB capable or 99% DCI-P3 or some similar color hype. Apple monitors, phones and tablets are capable of near DCI-P3 colorspace. Ideally, you should use a colorimeter to tune your computer signals to map to the capabilities of your specific monitor. as these do change over time when the display ages. If you do not have a colorimeter, then you should use one of the generic color profiles shown in the chart below that matches the spec of your monitor.

 

[Johan Elzenga]

I accidentally exported an image to PS using the default ProPhotoRGB, and then sent that TIFF, with ProPhoto RGB colour space embedded, to a professional printer. The image came back completely washed out. When I converted the profile to sRGB in PS in looked the same on screen and printed fine

I wouldn’t call this a ‘professional’ printer, because there is a clear and simple explanation for this. The printer did not use proper color management. They did not read the embedded ProPhotoRGB color profile as they should have done, but simply assumed that all their customers send sRGB images so there is no need to check that. Many consumer print shop do indeed work that way, a professional print shop should know better.

If you send the image as ProPhotoRGB to a real professional print shop, you will get a noticeably better print (assuming the image does contain more colors than sRGB can contain).

 

[clee01l]

If you send the image as ProPhotoRGB to a real professional print shop, you will get a noticeably better print (assuming the image does contain more colors than sRGB can contain).

A 'real' professional will not only specify their color profile to use and if they do accept sRGB or AdobeRGB, will read the images and convert it to their own color profile. No one should be using sRGB in a print specification. Although a sRGB file will certainly not contain any out of gamut (envelop) colors .

 

[theferret]

Thanks for all replies. I think they will accept sRGB or Adobe 1998 so assume the later is better starting point.