Colour Picker Wrapup#
When running an application with many changes in real time it is important that the changes are carried out in the fastest way.
The following were new to me:-
Working with arrays to produce gradients and chequered output
Save arrays as PPM files then directly import into tkinter
Emulating alpha changes on RGB files (no alpha channel)
Writing range values for Scale adjusted to scale width and cursor width
Controlling cursor movement in a canvas
Gradient changes for the colour components
Expanding a widget containing an image
Say we wish to have different colour schemes other than hsv, then hsl is a good candidate, it should follow a similar method to hsv. Whatever colour scheme is chosen it would be a good idea to include rgb since that is the base for displaying colour on the monitor.
Printing in CMYK#
Printing operates in CMYK is a subtractive system so whereas (255, 255, 255) in RGB gives white, a combination of CMY produces a dark grey approaching black, hence the need for the black - quite apart from reduced cost it gives a better rendition of darker colours. Printers designed for photographic output will have additional inks, probably a photographic black and grey cartridge - so six inks in all. Unless you have access to a good printer the results could be disappointing because printers render a different colour range.
Generally rather than converting pixels we require image conversion to preview the results before printing. The problem is that the result will be displayed in RGB at our computer and the CMYK rendition will at best be a good approximation, which may or may not show all the problems. A good image from the camera will carry its own embedded colour profile, so this is required for commercial printing.
At home always test the result on the printer - try out photographic paper - but also be prepared to use good quality matt paper. Calibrate all the hardware especially the monitor, do not expect that results can be easily duplicated on different printers, or even the same printer at different times. If all else fails use the chain chemist's photographic printers, rather than investing in a rarely used expensive printer.