Black Dye

[lightway]

Any experience in running black dye cold (ambient) as opposed to suggested 140 deg.
Occasionally, I get a dark blue, my thoughts are that the structure is closing before full dye penetration occurs.

[sswee]

Originally Posted by lightway

Any experience in running black dye cold (ambient) as opposed to suggested 140 deg.
Occasionally, I get a dark blue, my thoughts are that the structure is closing before full dye penetration occurs.

The dye works best at 140 degrees. Some have said they use it at room temp but the problem of a dark blue color usually is old dye or too thin of a anodic coating. Since it is an occasional problem and seeing your other post I would think that too thin a coating would be the most likely cause. Do you use the 720 rule? What CD do you use? What PS are you using?
SS

[acidrain]

I have found that you have to anodize to a full 1mil coating thickness for a deep black color. Use the 720 calculator.
Although the black dyes very easily, I have not had good results dyeing at room temperature.