[SML] Subject: advice on some old pigment

[Brent Logsdon]

It is many years since I used dry pigment but I loved the colors I could get.  It can almost have the vibrancy of pastel. I no longer even have my reference books. I have a couple of general pointers that I don't think anyone has mentioned yet today.  They may apply if you are decide to use the pigment you have.


1) Mix the pigment into a paste before mixing it into the binder (sizewater, untinted latex base, polycrylic, Rosco Clear, etc.)  You will have fewer clumps if you fully wet the pigment into a paste.  You also only have dust when you make the paste. You can make the paste in an improvised glove box and then mix the paint in the open.  It is also much easier to match tints using a paste rather than a powder.

2) Only mix enough paste to use in a day or so.

3)  If mixing organics like umbers and siennas you get better shelf life if you use distilled water.  There is less chance of critters to turn the paste sour.  Bad raw umber is noxious even before you add the rotten milk of old casein or the funk of old hide-based glue water.

4) Some pigments do not like to mix with water.  For these you can make the paste with denatured alcohol.  If you find the color changes with how many strokes you make then you have a pigment that is slow to wet.  You are actually breaking up tiny, dry pockets of pigment with each stroke. This may dry to a uniform color if the binder clears on drying.  If you have mixed into white latex then you will probably get streaky finish.


5) You can rarely over - stir unless you start to get foam.  Some pigments are so heavy they settle between brush loads.  Cheap pigments or mixed colors may not settle evenly.  I've done occasional rough scumbles using only one bucket of paint solely by mixing only rarely.  The changing color as the different pigments settle created sufficient variation.

6) Oil of peppermint or oil of clove were often listed to retard spoilage. I have used neither.  I did use formalyn a long time ago but not in decades.  It is formaldehyde and not safe.  It really toughens up a protein-based binder, however.

7) Color-shift on drying is variable.  Test carefully and only match dry to dry.

8) If you don't have books in the theatre department of the library that give you enough info look for older artist's bibles for mixing distemper, tempera, and casein.  Fresco info will be of mixed use because you are much less concerned about changing the pH level of the paint than someone working with wet lime plaster. Fresco secco info is more useful than wet plaster fresco info.


Brent Logsdon 
Chisholm Trail Controls LLC 
1812 Schooner 
Norman, OK 73072 
(405) 924-0349
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