11. Transparency

11.3 Basic compositing computations

11.3.5 Blend mode

...

Add the following NOTE after both Figure 72 and Figure 73 as follows:

NOTE: "Figure 72 - RGB blend modes" and "Figure 73 - CMYK blend modes" are not intended to be pixel- or color-precise, but just indicative of the style of visual effects generated by the different blend modes in an additive RGB space and subtractive CMYK space respectively.

11.6 Specifying transparency in PDF

11.6.6 Transparency group XObjects

Change Table 145 as follows:

Table 145 -Additional entries specific to a transparency group attributes dictionary
Key Type Value
CS name or array

...

The group colour space shall be any device or CIE-based colour space that treats its components as independent additive or subtractive values in the range 0.0 to 1.0, subject to the restrictions described in 11.3.4, "Blending colour space". These restrictions exclude Lab and lightness-chromaticity ICCBased colour spaces, as well as the special colour spaces Pattern, Indexed, Separation, and DeviceN. Device colour spaces shall be subject to remapping according to the DefaultGray, DefaultRGB, and DefaultCMYK entries in the ColorSpace subdictionary of the current resource dictionary of the transparency group XObject (see 8.6.5.6, "Default colour spaces").

...

Last modified: 15 September 2023