#693 Canon Selphy CP1200 Black and White Photos have a Green Hue
My Canon Selphy CP1200 photos have a green hue when printing black and white photos.
TO REPRODUCE
1) Add the drivers CP1200 drivers to the Gutenprint source code attached to Ticket #690, "Add support SELPHY CP1200, Improving the overall impression for SELPHY USB." Note: As far as I know, the patches only add driver support and adjust the contrast level. No color adjustments are apparently made.
2) Make a black and white printed photo using Gimp Gutenprint, by first selecting "Desaturate" within the "Output > Adjust Output" Gutenprint settings. (Albeit, choosing Desaturate seems to make no difference, whether selected or not for black and white prints.) Notice the black and white printed photos have a green hue or green cast within the white areas of the black and white photo.
TO TEMPORARILY FIX
1) Perform the above, however within Gutenprint "Output > Adjust Output" settings, manually reduce the Green channel by one point or one integer value. Notice black and white printed photos no longer have a green hue or tint to the white backgrounds.
I'm unsure if this also effects color photos. I own no color profiling hardware.
I'm using gutenprint-5.2.11, with Bug #690 patches.
I really need to get some color profiling hardware to further any color issues, as I'm having a difficult time distinguishing color output differences using only the naked eye.
Last edit: Roger 2016-02-22
You may want to try the selphy_go tool that allows you to print jpegs directly to the printer using wifi. I fixed a bunch of bugs and forked it until the author incorporates my patches: http://git.shaftnet.org/cgit/users/pizza/public/selphy_go.git/
But in a general sense, yes, any attempts to meaningfully calibrate the printer's output will require use of a spectrocolorimeter. It's on my wish list...
FYI, I just added a dedicated backend for the newer SELPHY CP models (820/910/1000/1200) -- it maeks printing a lot more reliable by reading back the printer status, handlig errors, and implementing the necessary printer-specific flow control.
Hey, good news -- I figured how to get the printer to accept YMC data, yielding results that appear identical to the older SELPHY models. Let me know if you'd like to give this a whirl before I enable this code for everyone.
Yup. I'm here!
I'll be glad to go ahead and try what you have.
I'm closing this as an obsolete ticket; the native-YMC output for the newer CP series has long been committed, resulting in better color output. Additionally, a more recent commit landed that fixes gamma curve problems, resolving the last known color issues vs Windows.
If there's still problems with the output (with 5.3.4-pre or newer) holler, and I'l see what I can do..