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10-09-2014, 10:31 AM   #1
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RGB-sRGB

Ok, what one do I use? What, or is there a benefit to sRGB? Thanks again

10-09-2014, 10:39 AM - 1 Like   #2
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Some claim that AdobeRGB is superior and allows more green tones, and ProRGB is even better. But I don't think this affects what the camera records. What is more important is that you have the same colour space selected in your camera and your developing software. sRGB is best for internet and computer usage, especially if you upload things. You see, some websites automatically resize your photos if they don't fit a certain standard. When this happens, the quality can be lowered, especially if the website also changes the colour space.
So be mindful of the colour space throughout your photo development, but don't worry about it too much. sRGB is good enough and I doubt anyone can notice a difference in real life, even if some of the other options have a theoretical advantage.
10-09-2014, 11:13 AM   #3
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AdobeRGB supposedly has the better color compression (though I believe that's more technical than noticeable) but most of the world uses sRGB. Computer screens, the internet and even printing services live in an sRGB world. If AdobeRGB gets misinterpreted somewhere along the processing line the image colors will look very dull and washed out.
And if one doesn't take care about this it's easy to mess it up, hence I go with sRGB (although my display would support "99% Adobe").


As I recently learned in another thread on PF, though, RAW doesn't contain any color compression. Color space is added when processing the RAW file, so it doesn't matter until then.
10-09-2014, 12:04 PM   #4
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QuoteOriginally posted by Storm Chaser Quote
Ok, what one do I use? What, or is there a benefit to sRGB? Thanks again
I'm afraid I don't quite understand what you are asking about here. sRGB refers to a color space; RGB, however, is a color model relevant to non-photographic applications as well.

Folks above introduced AdobeRGB (1998) to the thread, so perhaps this is what you are interested in? AdobeRGB has a wider gamut. To me the color space choice depends on your output requirements. sRGB, as noted, is right for web postings. If you need high quality printed output, then AdobeRGB will get you a better product provided, and it's a big if, the printer can play along. . . some can, most cannot.

If you work with raw files it doesn't matter until output time. It's better to start with the broadest possible color space (ProPhoto RGB) and dilute from there.

M

10-11-2014, 04:11 PM   #5
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sRGB will give you more saturated images off the camera as Adobe RGB will not. It seems that everyone like saturated images nowadays. Both can be fixed to your liking in post process.
10-13-2014, 04:31 PM   #6
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Miguel, sorry my question was the difference between, AdobeRGB and sRGB. Thank you for the repleys and have found my answer.
10-14-2014, 02:13 PM - 1 Like   #7
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AbobeRGB(1998) was developed with the intention of "colorspace and gamut" translation between a digital source and a CMYK analog output. In other words, as long as your pictures ARE NOT INTENDED for commercial printing via offset printing (magaxines, etc), then there is no need for using AbobeRGB.

But today and since the standardization of "prepress Abobe Acrobat PDF files" as the digital source for the prepress negative or direct place production, there is no need for using color profiles and in fact, AdobeRGB embedded pictures can trick your monitor an eyes into incorrect color balancing and adjustments.

The color profile embedding for prepress was "mandarory" when the sources for prepress came from different platforms or programs, like photoshop, quark express, pagemaker, ilustrator, corel, etc. Now, all those souce files are first converted (or created) as AdobePDF /x1-a which takes care of stadarizing resolution, color space, pixel density, change all RGB color into equivalent CMYK color, create true black items from RGB 0,0,0 objects, and the most important adjustment for commercial printing purpose, which is: DOT GAIN ADJUSTMENT according to intented printing media. Don't crack your brains figuring out what the hell is Dot gain... Just know that a set of printing plated created for newsprint paper, will producevery dull and washed results on shinymagazine cover paper. OTOH, if plates are for magazine cover, they will produce dull results on newsprint paper. That Is because papers have different rate and degree of ink absorption and dry times. The longer it takes to dry or the higher ink absorption, will produce bigger dot gain ( enlargement) and thus, an oversaturated image composed exclusively of CMYK dots.

In short words. If doing Only home printing, you can stick to AbobeRGB, it may give you a slight wider gamut around the greens and adyacent colors like yellow and cyan, but ONLY if your monitor iscorrectly adjusted and meets the color standard (not easy )

Stick to sRGB if planning on external sources for printing, if supplying images for commercial use or selling "stock". Monitors are easy to adjust to sRGB colorspace. Always use sRGB (24bit) files for home or pro printing. Never suply CMYK files unless your printer demands it, an even so, the will askfor certain colorpace.

The most common accident in colorspace (color profile) conflict, happens when the source of the picture delivers a CMYK image with Adobe RGB profile embedded. Then, the publisher uses the file "as is" to create the PDF X/1-A prepress file to create the plates.

This plates are used but no matter how much adjustments in ink flow an delivery are tried at the offset press, the image has two distintive characteristics: oversaturated greens and dull to dark reds. Why? Color profile was aplied twice and on incorrectly (AdobeRGB incapable) monitors.,

Hope this sheds some light on the sRGB /AdobeRGB difference, why do they exist an how to live withthe taking full advantage of their capabilities.

Last edited by rburgoss; 10-14-2014 at 02:24 PM.
10-14-2014, 07:54 PM   #8
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QuoteOriginally posted by rburgoss Quote
Hope this sheds some light on the sRGB /AdobeRGB difference, why do they exist an how to live withthe taking full advantage of their capabilities.
Thank you for your detailed explanation. The historic framework and intent is often helpful. Here is my take on the color space mess:
  • Most devices support the relatively narrow gamut of the sRGB color space as a lowest common denominator
  • Most currently-available computer monitors support a fairly broad color gamut supported by either the maker's profile or by settings generated by some sort of calibration protocol. The available gamut is usually much broader than what sRGB provides.
  • Processing software such as Adobe Lightroom often operate in a broad gamut environment. In Lightroom, the Develop module operates in the very broad ProPhoto RGB space. The other modules use the somewhat narrower Adobe RGB space. Lightroom provides the "Soft Proof" feature to allow a preview of the image in sRBG or other color spaces.
  • What you see on your screen is a union of the software support and the hardware settings. What that means is that out-of-gamut colors on your monitor may look different than those same colors on another computer system.
  • Runtime down-mapping of out-of-gamut colors to sRGB is a common source of really crummy looking digital photos. The same may be true for explicit conversion to sRGB by your tool of choice.*
  • The image files have the option to embed the intended color space information as metadata. However, embedded profile information is problematic if the display software is not color space aware (Google Chrome team, are you listening?) or if the feature is not enabled by default. Non-aware software defaults to the system display profile, sometimes with disastrous results.
Conventional wisdom and the scheme most likely to provide the most flexibility and consistency in terms of target (computer monitor vs. consumer printer vs. traditional CMYK offset print vs. service bureau vs. commercial ink jet printers vs. whatever) goes something like this:
  • Calibrate your monitor to the full extent of its gamut support. Avoid using the sRGB profile. Doing so means you are working more or less blind in regards to out-of-gamut colors that may be generated in PP. sRGB feels good, but has hidden traps.
  • Do all post-processing and editing in a broad gamut. Tool support varies in this regard and some makers give you little or no choice. The ProPhoto RGB used by Adobe in Lightroom's Develop module** is intended for photo editing and allows for huge flexibility with minimal artifact.
  • Explicitly down-map to a narrower gamut based on the intended publication target. In Lightroom, this is an option on export. For the Web this would be sRGB with perceptual rendering intent. Always preview before publishing. For home ink jet printers, the default drivers usually do a decent job. For commercial printing, work with your vendor.
If none of the above makes sense there are numerous resources on the Web explaining color space, gamut, color profiles, and options for output. The Cambridge in Color Web site has a useful tutorial:

Tutorials on Color Management & Printing


Steve

* A good example would be what the PEG judges here on Pentax Forums see for submitted images. The preview images are generated by the forum software and feature a coercion of the original gamut to sRGB. It is not unusual to receive JPEGs with an embedded Adobe RBG profile. These look great on a color-aware browser and are readily available for viewing by clicking through on the preview. The rub comes when the original image is mostly out of the sRGB gamut and the preview image generator does a clumsy job of down-mapping. If the judge is lazy and does not click through, even good work may be rejected. I usually add a comment suggesting an explicit conversion to sRGB prior to submission.

** The color space used by Lightroom is actually a variant of ProPhoto RGB often referred to as "Melissa RGB". It uses the ProPhoto RGB color space with the sRGB gamma. Are our brains full yet?


Last edited by stevebrot; 10-14-2014 at 08:21 PM.
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