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View Full Version : Urgent, mulling problems!!


helmarshausen
06-03-2006, 11:25 PM
I am new to egg tempera and am having trouble. I use a muller to mix the pigment into water to make the paste. My yellow ochre, no matter how long I mull it, continues to have tiny, tiny, clumps which are a real problem when I mix it into egg and put on the gesso panel. I've read here that some of you just mix the pigment in a jar with water by shaking it!

How in the world, if mulling it isn't taking out the lumps, is shaking it in a jar with water going to solve that problem?

Do I need more tooth on my muller and slab?
Is yellow ochre just a difficult color?

what do I do?

Roger

Georgeoh
06-04-2006, 07:02 PM
How in the world, if mulling it isn't taking out the lumps, is shaking it in a jar with water going to solve that problem?
The advice to shake pigments in water is probably the most inaccurate and inept advice about dispersing pigment in water that I have read. Paint manufacturers use high-speed dispersion mixers and attrition mills to disperse pigment in wetting solutions, so I cannot imagine how shaking in a bottle could achieve anything even close.


Do I need more tooth on my muller and slab? Is yellow ochre just a difficult color?
Yellow ochre is not a particularly difficult color to disperse, so if you have large lumps than continued grinding may be in order. If the lumps are very small you may be experiencing the the discrete particle size of the pigment, which for earth colors is quite natural and common, and hence you may want to levigate (wash) these out or perhaps find a different yellow ochre.

Bert Congdon
06-05-2006, 11:51 PM
I add ox-gall to the water. I get it from Kremer. I found that viridian needed it the most.

Alessandra Kelley
06-17-2006, 04:33 PM
I shake pigment in water to wet it before I mull, so it makes less of a powdery mess. I have had some bad experiences with poorly mulled pigments, and recommend that they be properly mulled.

Georgeoh, what's your opinion on using a mortar and pestle to mull? I've had to resort to it at times. I think the average layperson (if there is such a thing) would be more likely to try it with less expensive, easier-to-find tools.

Georgeoh
06-17-2006, 06:51 PM
...what's your opinion on using a mortar and pestle to mull?
You can use a mortar and pestle to disperse pigment in water (or the paint vehicle of choice), but it is not as effective as a muller and slab. You can disperse more pigment faster with a muller then in a mortar and pestle. A mortar and pestle is best used to grind pigments in dry or wet form.

dcorc
06-17-2006, 10:02 PM
Sounds like the original problem though, is that pigment particles are large enough to be gritty - so surely in that particular case, a pestle and mortar are what is required initially for grinding, followed by a muller and slab for dispersal.


Dave

RobM
06-19-2006, 04:04 PM
I would seriously suspect the quality of the pigment if you have some lumps in it. I only get my pigments from a reputable source and will not change. Cornellisen's (Can never get their correct spelling!!) have over the past 20 years provided me with pigments which I know and trust.
In the main I just stir in the water to make a jar of paste, too much painting time taken up with mulling, however, some earth colours such as burnt umber and yellow orchre do need a little bit of mulling.
Rob

Dimitris C. Milionis
06-20-2006, 06:22 AM
Is yellow ochre just a difficult color?

what do I do?

Roger


just change your supply to a better fine product,

I have noted before that it is wiser to pick up a good quality watercolor in 5 or 10 ml tube, water it out with a 1:4 water ratio, let it sit until the pigment sits take away the water which will also take out over 70% of the gum etc. an there you are with a fine pigment, if you want repeat the process to take out more gum etc.