Step 9: Coating the Magenta Layer

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.
This is a really fabulous instructable and your results are amazing. Great work! <br> <br>I do wonder, however, whether it's wise to wash dichromate, and indeed cadmium yellow, down the sink.
<p>Dichromates are poisonous, so it's definitely not a nice thing to add flush down the drain, but it's so diluted by the time it's rinsing off the print, I would think it isn't a huge deal. Perhaps more important to note is that potassium dichromate is an oxidizer (will add fuel to a fire), so you definitely should not throw it in the waste basket. Washing it down the sink with water is the safest thing for your home/studio. </p>
The amount of pigment is ridiculously small. Think of the millions of watercolorists out there using cadmium yellow and washing their brushes in the sink. We should probably concentrate our cadmium concerns on batteries. <br> <br>The dichromate I ride the fence on. Recovering the water from the first wash, which should be a gallon or two, for recycling would eliminate the vast majority of the dichromate from going down the drain. On the other hand, storing six gallons of water per print (and I usually work three at a time...18 gallons total) until I can take it somewhere, where it'll be treated by even more harsh chemicals...you get the idea. <br> <br>Thanks for your kind words.
<p>This instructable is really great, a lot less intimidating for a beginner than the article on gum printing on the website about alternative photography we all know (If you don't, you can spend ~10sec searching to find it). When I finally get around to try this, I don't think I will do tri-color right away, monochrome will be just okay (And I like monochromes).<br><br>I don't know, whether You are still active or not, but if You could make a similarly informative and easy-to-follow instructable on paper sizing, I would be thankful.</p>
Brilliant! <br> <br>Thank you SO MUCH for sharing this process. Your instructions are clear and well written, and the process its self is fascinating. <br> <br>I have even MORE respect for those early photographers, (Imagine lugging an old plate camera around Yosemite), where things could go TERMINALLY wrong at any of a dozen and one different points allong the road from taking a picture to hanging a finished print. Even understanding the chemistry only helps you SO FAR. <br> <br>I'm dying to give this a go some time. <br> <br>Might have to build a camera first... <br>
Great Instructable!!
It's just a wonderfull work, really really nice work. I love it. It reminds me the polaroid pictures. <br>The proces is a little bit similar to the three color screen print. <br>Probably i can't do it, but is a nice work, i will give it a try someday. <br>

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