In the Color Space article we introduced the color spaces that are commonly used when we work on our photographs \u2013 proPhoto RGB (the most complete), AdobeRGB and sRGB (the most limited).\u00a0 Each of these color spaces was compared to a box of Crayons with proPhoto RGB being represented by the 92 count box, AdobeRGB by the 64 count box and sRGB by the 48 count box. The color of the paper itself also affects its color space.\u00a0\u00a0 Some papers are pure white and to achieve this they very often contain chemical brighteners.\u00a0 These papers will have a larger color space.\u00a0 Papers without brighteners may still appear white but they won\u2019t have as large of a color space.\u00a0 And some papers are not even white but have a pale yellow cast.\u00a0 Not only will this affect the color but it also reduces the color space.<\/p>\n Now comes the big question.\u00a0 What happens when the colors in your photograph cannot be reproduced in the paper\u2019s color space?\u00a0 Or stated another way, what happens when there aren’t as many Crayons in your paper \/ ink\u2019s color space as there are in your photograph\u2019s color space?\u00a0 Well, it\u2019s not\u00a0 a problem if you only use Crayons in your photograph\u2019s color space that are also in the paper \/ ink color space.\u00a0 But that\u2019s no good.\u00a0 You may want to print the same photograph on a different paper with a larger color space.<\/p>\n When you have colors in your photograph that cannot be reproduced in your paper \/ ink color space you have Gamut Errors<\/strong>.\u00a0 Boy these can be annoying.\u00a0 And they can be puzzling too.\u00a0 You may have areas of your photograph that don\u2019t have any apparent highlight clipping (they\u2019re not pure white) but they still don\u2019t have any detail.\u00a0 This is because colors outside the paper \/ ink color space are printed at the outer limits of that color space.\u00a0 For example, if you have a really intense blue Crayon in your photograph\u2019s color space but a less intense blue in your paper \/ ink color space, the image will be printed with the less intense blue.\u00a0 And not only the photographs intense blues but also the its less intense blues.<\/p>\n Remember the CMM (Color Matching Module)?\u00a0 That\u2019s the software on your computer that basically translates colors in your photograph\u2019s color space to the same colors (but a different set of RGB numbers) in your paper \/ ink color space.\u00a0 When the colors in your print fall outside of the paper \/ ink color space the CMM is responsible for dealing with that.\u00a0 You can specify how you want it to handle this by specifying the Rendering Intent<\/strong>.\u00a0 And that\u2019s what rendering intent does \u2013 tells the CMM how to render colors that fall outside the color space of the medium you\u2019re printing on.\u00a0 Therefore,\u00a0 rendering intent is part of the print dialog.<\/p>\n There are four rendering intents, two of which we use in photography.\u00a0 Here are the four but I\u2019m only talk about the two we use \u2013 Saturation, Absolute Colorimetric, Relative Colorimetric and Perceptual.\u00a0 It\u2019s the last two \u2013 Relative Colorimetric and Perceptual \u2013 that we use.<\/p>\n We\u2019ll do Relative Colorimetric first because this is what was described in the example of the blue colors above.\u00a0 The blue that was out of gamut was translated to the nearest blue at the edge of the paper \/ ink color space.\u00a0 None of the colors that are in gamut are changed.\u00a0 Which is the way relative colorimetric works \u2013 colors in gamut are not touched (other than the translation of their RGB numbers from one color space to the other).\u00a0 But colors that are out of gamut are translated to the nearest color at the edge of the color space.\u00a0 Theoretically, relative colorimetric preserves the color at the expense of saturation.\u00a0 As a practical matter, I find that relative colorimetric produces images with sharper contrast and often a little darker than the alternative, Perceptual. Let\u2019s put it all together.\u00a0 First, calibrate your monitor.\u00a0 Next, use a large color space for your images in post processing such as proPhoto RGB or AdobeRGB.\u00a0 Do not use sRGB for your photos.\u00a0 Finally, when you print use the CMM of the print program, not the operating system, specify the ICC profile for your paper \/ ink combination, disable color management in the printer and select the rendering intent that gives you the best results.<\/p>\n Do you have experiences and thoughts on color management?\u00a0 We\u2019d like to hear from you; add your comments.\u00a0 And if you know someone who might find these articles useful, please feel free to share it with them, Like us on Facebook, repost it on your website or blog.<\/p>\n Join me on an upcoming workshop.\u00a0 Click here for more details.<\/a><\/p>\n![\"crayons_96cnt\"](\"http:\/\/ralphnordstromphotography.com\/wordpress\/wp-content\/uploads\/2013\/07\/crayons_96cnt_thumb.jpg\" "\\"crayons_96cnt\\"")
<\/a> In the Computer to Print article we talked about the different types of print paper and inks and how each has its own unique color properties.\u00a0 That is to say, each paper \/ ink combination has its own color space.\u00a0 And the size of the color space (number and colors of Crayons) varies from one combination to the next.\u00a0 The size of the print\u2019s color space depends on the type of paper.\u00a0 Glossy papers are at one end with the largest color spaces and matte papers are at the other.\u00a0 Luster papers are very close to the color spaces of glossy papers.<\/p>\n![\"rendering](\"http:\/\/ralphnordstromphotography.com\/wordpress\/wp-content\/uploads\/2013\/07\/rendering-intent-rc_thumb.jpg\" "\\"rendering")
<\/a> With perceptual the colors that are out of gamut are mapped back to the color space just like relative colorimetric.\u00a0 The difference is that the colors within the color space are also altered, they all get moved closer to the center of the color space.\u00a0 I think of it as being very similar to what I used to do as a kid with a rubber band.\u00a0 I\u2019d stretch it out and write my name on it with a ball point pen. Then let the rubber band return back to it\u2019s regular size and all the letters would get very narrow scrunched together.\u00a0 It was cool.\u00a0 Perceptual preserves saturation but may result in some color and tonality changes.\u00a0 And my experience is that the image tonalities are softened. ![\"rendering](\"http:\/\/ralphnordstromphotography.com\/wordpress\/wp-content\/uploads\/2013\/07\/rendering-intent-p_thumb.jpg\" "\\"rendering")
<\/a> I routinely use both rendering intents and it would be hard to say which one I use the most.\u00a0 I like relative colorimetric for it\u2019s more dramatic look due to the contrast.\u00a0 But often times the shadows become blocked so I switch to perceptual which does a better job of preserving shadow detail or when I want a softer look.\u00a0 It can be a nightmare to keep track of which rendering intent I use.\u00a0 So once I find the rendering intent that I like, I change the file name by appending the rendering intent to the end.\u00a0 The file name may end up looking like big_sur_pfeiffer_beach_130804_rrpm_rc.tiff <\/strong>for a photograph that works best with relative colorimetric (rc) rendering intent printed on Red River Polar Matte (rrpm) paper.\u00a0 See File Naming Strategies<\/a> for more details.\u00a0 I find that I routinely print two, three, four or even more proofs, tweaking this and that including rendering intent until I finally get the results I\u2019m looking for.<\/p>\n
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