In wiki (https://colorwiki.com/wiki/ColorThink_Pro_-_Grapher#Working_with_Images_and_Lists), after saying “… ColorThink Pro attempts to map every pixel in your image…”, it says “Due to the slight warping of Lab space, and the rounding of color numbers in the process of quantifying colors, the Grapher might not display every single pixel in an image.” What does this exactly mean ?
Also, if worksheet is used to extract unique colors, it says “… This procedure creates a color list for each of the colors in the image (which are different enough to be humanly distinguishable).” Is different enough to be humanly distinguishable a dE check ? So it does not find unique colors in RGB but find distinguishable colors in Lab ?
When referring to colors, we mean Lab values, otherwise it will typically refer to device values.
As for graphing color, large images produce too many individual color values for the Grapher to still perform with reasonable speed. Larger images will be down-sampled before turning into a list for graphing. The idea has been to produce color for graphing that gives an effective visualization of image colors rather than a 100% accurate one.
In ColorThink 4 we allow for larger images before downsample occurs and also have some simple image recognition to help detect if an image is likely a color target. Color targets tend to have sharp transitions and many fewer colors so if CT4 detects a target, it will use nearest-neighbor-style downsampling to avoid creating extra intermediary colors.
