[SML] Subject: advice on some old pigment

[Richard John Archer]

On Oct 11, 2014, at 4:48 PM, Brent Logsdon via Stagecraft wrote:

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

1)  This is what I did as "paint boy"  when  working for painter Bob Benstead at Kansas City Opera and for Starlight  Theatre (outdoor)in Kansas City in 1971-73
      We used little five quart plastic buckets for the wet paste

2)  We mixed much more than this--maybe an inch to two in the bottom of the bucket.  I think Benstead used a palette of  eleven to thirteen colors plus black and white.

3)  We used distilled water and

4) alcohol---I remember especially Prussian Blue not mixing with water at all.

On Friday, before quitting for the week we stirred everything well then covered the  top to the mixture with about 1/4" of water to prevent drying out.  Then we covered with plastic wrap.   On Monday morning, we'd re-stir well and then start

5)  I don't remember getting foam.  We re-stired everything at least twice a day and usually before we scooped any out for color mixing.

6)  Never used anything for spoilage at the opera.   Starlight, because it was outdoors,  used to spray the painted scenery with formaldehyde to "waterproof" the paint job.  I don't remember if we put any in the paint……respirators???…what were they???

7)  Benstead was always smoking, he used the heat from his cigarettes to dry the paint as he dabbed it onto the acetate covering the designers paint elevations.
      BTW, he died from cancer.

8)  We were using a dry  powdered casein glue (Casco form Bordens) which we mixed with water (cold would do although hot was better) to form our size.  For this we used KCMO tap water.  All the canvas scenery and much of the rest was primed with a mixture of size water and (Danish) Whiting which is finely powdered calcium carbonate.  This sealed in any wood oil (pitch) and gave the canvas a good "tooth" to hold the paint similar to using water colors on a good cold pressed illustration board--like a Bainbridge #80



Don't ask me what I was doing yesterday, I won't remember

DickA
TD, Cornell U.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://theatrical.net/pipermail/stagecraft_theatrical.net/attachments/20141011/288f06c3/attachment.html>