Instructables

Tri-color gum bichromate prints from digital images

Featured

Step 9: Coating the magenta layer

Picture of Coating the magenta layer
9 - magentacoat.png
9 - clean.png
9 - cleanup.png
Now that the yellow print layer's dry, time to print the magenta pigment layer, which requires the green negative.

Repeat: Time to print the MAGENTA pigment layer, which requires the GREEN negative.

Mix magenta pigment the same way as yellow: one gram pigment plus 5 ml gum Arabic.  Mix, mix, mix.  Add 5ml sensitizer.  Mix, mix, mix.  This is being treated here with brevity in the interest of humor and well, brevity.  Be nice to your print.  Don't rush.  You're going to be here a while.

Perform this step in normal incandescent (non-UV) room lighting.

Coat evenly within pencil marks directly over the previously printed yellow pigment layer.  This process is astounding in that the deeper into it one progresses, the uglier the print becomes...until the very end.  It's horrible.

This layer will be more difficult to smooth than the yellow layer.  Notice the pictured wide hake brush that was used to lightly brush over the coated surface of the print to blend the finish.  A light touch is required.

Hang to dry thoroughly about 20-30 minutes.  In the meantime, clean your mess, and clean your print frame.  Dust is your enemy.
 
Remove these adsRemove these ads by Signing Up