Use of ProphotoRGB color space?

[sharath.1628]

Dear All,

Could you please explain me this.

What is the use of a colorspace like Prophoto RGB

I Keep reading that these are used by photographers and it is a large colorspace.

I hope this is correct. A monitor mostly uses SRGB color space for display and similarly a printer uses a CMYK color space.

Both these color spaces are smaller than the Prophoto. So what is use of having a image in a colorspace, in which the colors cannot be viewed in a monitor or printed using a Printer.

In a printer we can increase the range of colors by adding the colors but what about a monitor.

Thanks

 

[Elroachio]

This article might be of interest
Understanding ProPhoto RGB

 

[Stephen Marsh]

I have not read the article yet, however my understanding is that it is all about preserving the gamut of the captured scene as much as possible when rendering from raw camera data - so that the colour can then be transformed into an output destination colour space using the perceptual ICC rendering intent. So, a wide gamut RGB working/editing/intermediate colour space such as ProPhoto RGB is often favoured by Photographers.

Many photographers cringe at the thought of clipping any colour channel data!

 

[Lukas Engqvist]

Prophoto is nostalgia of Ektachrome

Prophoto is nostalgia of Ektachrome

It has more colours, but there are some serious problems with strange warp on dark colours, and also look at a large number of colours that missing (even sRGB has more colours in the central area, and just having some extreemes isn't so practical in my opinion.

 

[TerryWyse]

What is the use of a colorspace like Prophoto RGB

I Keep reading that these are used by photographers and it is a large colorspace.

I hope this is correct. A monitor mostly uses SRGB color space for display and similarly a printer uses a CMYK color space.

Both these color spaces are smaller than the Prophoto. So what is use of having a image in a colorspace, in which the colors cannot be viewed in a monitor or printed using a Printer.

While it's true that most monitors are still "sRGB", there's more monitors coming out all the time that are closer to AdobeRGB...someday maybe we'll have something close to ProPhotoRGB and we'll be able to view all those "ProPhoto" images more accurately than we can today.

As far as printers, from a driver standpoint, most of them are actually treated as RGB devices (regardless of the actual inks they use) while RIPs mostly treat them as CMYK devices.....but what's actually important is the color gamut of the latest printers. Some of the latest printers, particularly the x900 Epson printers with their "HDR" inks plus orange/green, can actually push their gamut beyond the rather wide AdobeRGB color gamut.....so there's no guarantee that these won't someday start approaching ProPhoto's color gamut.

Botton line, ProPhotoRGB is more about protecting the integrity of your images for future advances in both monitor and printer color gamuts. There are some real "challenges" with ProPhotoRGB but if you want to protect your images for the future, ProPhotoRGB (or possibly, better yet, L*a*b* space) are your best bet.

My personal opinion is that the vast majority of natural photographic images don't approach ProPhotoRGB but it can happen with some images, especially those that have been edited to push their saturation and dynamic range such as HDR images.

Terry

 

[David Milisock]

Prophoto vs sRGB

Prophoto vs sRGB

Welcome to Bruce Lindbloom's Web Site

Try this site, this guy forgot more about color spaces then most know. He worked for Adobe and Corel at one time.

To put it in a nut shell prophoto is the conversion space from RAW of preference because for most natural captures you can achieve depth of color that cannot be obtained otherwise. It also allows archival of the most color, the shortcoming being with the current trend of true 16 bit Bayer capture patterns the use of Photoshop.

The limitation is the computer model of 256 shade per channel some natural captures such as those with ultra wide gamuts, (captures with neon lights) or solor radiation/sunsets can develop banding due to this computer limitation.

 

[Mike Strickler]

Pro Photo RGB was designed by Kodak as an archiving space for scans of Ektachrome transparencies without any clipping of colors. Is is indeed a huge space. But for that reason it makes a poor editing space. Tiny moves in curves result in very large color shifts, so it's hard to work with much subtlety. And 48-bit files (or Photoshop's 45-bit version of 48-bit, to be precise) is necessary to avoid banding and other artifacts in ultra-saturated colors as 256 steps won't smoothly span this extra range. The idea behind this space is that you can preserve even extreme colors that MIGHT someday be reproduceable in some as yet unknown output method.

I guess one would need to know more about what you are trying to do before making recommendations, but in general you can archive your RAW camera images in their native form (which uses PF as its native space) and scans in Pro Photo if you insist. Adobe RGB in practice is just fine for nearly any imaginable use, but if you have concerns about clipping some really extreme colors, the more usable (than Pro Photo) DonRGB or Ektaspace will preserve all the colors you will ever need and still allow you to edit fairly easily. sRGB definitely will clip some colors that you might print (cyans/blues/greens), so this is not the best space to start with for exporting from your camera, and you won't want to convert to it for editing or archiving.

 

[Correct Color]

What is the use of a colorspace like Prophoto RGB

I Keep reading that these are used by photographers and it is a large colorspace.

I hope this is correct. A monitor mostly uses SRGB color space for display and similarly a printer uses a CMYK color space.

Both these color spaces are smaller than the Prophoto. So what is use of having a image in a colorspace, in which the colors cannot be viewed in a monitor or printed using a Printer.

One time I had a a customer who needed to print a particular car company red. He needed to come absolutely as close to it as he could because he was going to print panels that would be applied to cars that suffered body damage during races.

We actually went out to a dealership and I measured several cars, actually, as there was more than one color. But it was the red that was the primary issue.

So we got back to the shop and I profiled one of his machines full-bore to make sure I got all the red it had to give, and, just by a hair, it was actually able to cover the L*a*b* value of the red.

However, while his printer covered it, Adobe 1998 and sRGB did not.

Here's an image of a slice of the gamuts of his printer, sRGB, Adobe 1998, and ProPhoto. The little black dot is the red we needed to hit.

This has always to me been pretty illustrative. It's obvious that just in terms of size of gamut, any of the RGB color spaces here are considerably larger in terms of overall color than this--or just about any--CMYK printer.

However, there are all different manner of CMYK inksets out there. This is a third-party ink for a particular brand of solvent printer that is not exactly common, but there are plenty of them out there. And this particular inkset can hit red. It can hit red so well that in an sRGB or Adobe 1998 workflow, there's machine capability left on the table. Including the specific red we needed to hit here. I wound up setting him up a ProPhoto workflow just for printing that red.

It's true that there are issues using ProPhoto and it's advisable to know what you're doing before you dive in, but the fact is that you don't need an exotic multi-color inkset to get advantage from it. This is an older CMYK solvent printer. And what's obvious by looking is that even though Adobe 1998 is--again--far larger overall than this printer's gamut on this media, there are colors this printer can hit both in areas of reds and darker green-blues that aren't in Adobe 1998.

And this is true of many inkjet printers. And, in fact, it's true more in the colors made up by CMYK than by exotic n colors. I find that n colors tend to increase gamut in areas that are in the gamut of Adobe 1998--typically oranges and light greens and purples--whereas it's not too uncommon on gloss media with aggressive ink limits on CMYK printers to extend particularly darker greens and blues well outside the boundaries of Adobe 1998.

So the technology is here today. Has been for awhile. The best reason to use ProPhoto is simply that once you throw color information away, there's no getting it back.


Mike Adams
Correct Color

 

[David Milisock]

3D sRGB in prophoto

3D sRGB in prophoto

A 3d shows prophot to be much larger then sRGB except aroung L97 blue area
Hopefuly this attachment shows up

 

[TerryWyse]

@Mike Adams...

Excellent example and explanation Mike.

As you indirectly explained Mike, it's usually not about entire color gamuts (or gamut "volumes") being bigger or smaller than one another.....but more about specific color regions. Even "offset press CMYK" can exceed something as wide as AdobeRGB in specific colors (cyans mostly) and inkjets can almost routinely exceed AdobeRGB in a few color regions.

Terry