Tips for choosing the right Rendering Intent
There are many aspects affecting color fidelity during the printing process, and printing the "right" colors is a subject that many books have been written about. The following section will attempt to give a brief overview of some points that may affect color fidelity in printouts and aims to provide a baseline checklist to avoid the most common mistakes.
Since Rendering Intents mainly deal with colors outside of the gamut, it is important to be able to see which colors are actually out of the printable gamut to help us judge which rendering intent is best suited.
The ErgoSoft RIP offers a function to visually display image parts that are outside the printer gamut: Select the image you want to check and select the Tuning command in the Properties window. Set the preview window to the 4-window option so that you can see the printer simulation in the lower two windows with the right one of them showing colors outside the gamut marked in a certain customizable color.
By default, out of gamut colors are marked in bright green, as visible in the Screenshot to the right, in the bottom right segment of the "Selection" window.
Note that the "Tune" option is only available for Raster Formats in Version 15.
Selecting Rendering Intents by Application
There are four rendering intents available in ErgoSoft RIPs that govern how out of gamut colors should be handled, each with different properties. While there is no definitive "right" rendering intent, there are some guidelines depending on the color space of the image and the origin of the image that can help us choose an appropriate setting:
- General Rules
When a majority of the colors used in an image are inside the printer gamut, use the Relative Colorimetric rendering intent.
When a lot of colors (Especially dark ones) in an image are outside the printer gamut, Relative Colorimetric with Black Point Compensation might be a good fit. If Relative Colorimetric with Black Point Compensation does not show enough details in the printout, Perceptual or Saturation might be better suited for this particular image .
- Colors selected from a color book
When all colors in the image have been selected from a color book that was printed with the same printer, printer settings, and ink on the same media as your image should be printed: use the same rendering intent that was used to print the color book.
- Reproducing colors
As long as the colors to be reproduced are in the printer gamut select the Absolute Colorimetric rendering intent.
When an image contains very light colors that are not printed when using the Absolute Colorimetric rendering intent, try using the Relative Colorimetric rendering intent instead.
When the Lab values of the colors are outside the printer gamut, try printing a color book from the Color books feature and visually select a similar color (with another Lab value) that is in the printer gamut. This value can then be used in color replacement to replace the out of gamut color, ensuring an output that is visually accurate.
Selecting Rendering Intents by Original Color Space
- Lab color space
When all of the Lab color space is used (from white to black), the color space of the printer is much smaller than the color space of the image. In this situation, the Perceptual rendering intent or Saturation should be the first choice.
If the colors from the LAB color space that are used happen to be inside the printer gamut,Relative Colorimetric should be used instead.
- RGB color spaces
The RGB color spaces are smaller than the Lab color space but in most cases still larger than a given printers gamut. For RGB, the rendering intent Relative Colorimetric with Black Point Compensation yields the best results in most cases. Perceptual rendering intent or Saturation are also suitable.
- sRGB color space (photos from a digital camera)
The sRGB color space is smaller than most other RGB color spaces but still larger than most printer gamuts. The rendering intent Relative Colorimetric with Black Point Compensation should be the first choice. Perceptual rendering intent or Saturation are also suitable.
- CMYK color spaces
The CMYK color spaces are smaller than the RGB color spaces. Since the printer color space is also (enhanced) CMYK, the CMYK color space of the image may be identical or in some cases smaller than the printer gamut. This means that in most cases nearly all colors will be within the printer gamut, which makes Relative Colorimetric with Black Point Compensation the recommended choice.
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