Home Forums Explore Media Casein, Gouache, and Egg Tempera Why not casein on oil ground?

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  • #449197
    Dharma_bum
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        If you can paint oils over a casein underpainting, why does Richeson warn against painting on an oil ground?

        Thanks,

        Dan

        [FONT=Garamond]Comments and critiques are most welcome.

        [FONT=Trebuchet MS]"Eventually, all things merge into one, and a river runs through it. The river was cut by the world's great flood and runs over rocks from the basement of time. On some of the rocks are timeless raindrops. Under the rocks are the words, and some of the words are theirs. I am haunted by waters."

        Norman Maclean

        #542225
        IfanJones
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            The casein is likely to dry before the oil and become crazed as a result.

            #542220
            Dharma_bum
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                But if the oil ground is thoroughly dry?

                Dan

                [FONT=Garamond]Comments and critiques are most welcome.

                [FONT=Trebuchet MS]"Eventually, all things merge into one, and a river runs through it. The river was cut by the world's great flood and runs over rocks from the basement of time. On some of the rocks are timeless raindrops. Under the rocks are the words, and some of the words are theirs. I am haunted by waters."

                Norman Maclean

                #542222

                You can try it if you don’t believe the conventional wisdom – you may not see any problems for years but casein is water-based and oil is, of course, oil based. Oil and water just don’t mix unless chemically altered.

                You can use oil over casein because oils need to be used fat over lean to prevent cracking/crazing – that means more oil in the upper layers. Casein over oil would be lean (little to no oil) over a fat (oil) base.

                Richeson recommends not using casein over an oil ground because they’ve been in the paint business for a very long time and know what will happen.

                #542224
                Harold Roth
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                    But if you were using casein emulsion paints, I think you could do it. Seems like it would be worth a try.

                    #542219

                    Casein and oil emulsion paint will definitely work on an oil ground.

                    David Blaine Clemons
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                    #542223
                    Trond
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                        I think it would very likely break the fat over lean rule. Casein is a glue binder, and the tubed version also contains a little oil. But casein needs very small amounts of binder overall to work. The resulting film is very matte and quite unflexible. Oil colors contain a lot of oil of course. It will remain moderately flexible for years. It might work on a rigid ground, with a thin layer of oil primer, but I wouldn’t think it is a great idea.

                        #542221
                        Dharma_bum
                        Default

                            Thanks for the replies. I guess I should have specified well dried oil ground over hardboard panel. The panels I have were prepared over a year ago. I would be using Richeson casein paints for underpainting, overpainting with oil.

                            Dan

                            [FONT=Garamond]Comments and critiques are most welcome.

                            [FONT=Trebuchet MS]"Eventually, all things merge into one, and a river runs through it. The river was cut by the world's great flood and runs over rocks from the basement of time. On some of the rocks are timeless raindrops. Under the rocks are the words, and some of the words are theirs. I am haunted by waters."

                            Norman Maclean

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