Casein Fixative
Fixative is a thin protective coating sprayed on top of dry media artwork, such as pencils or pastels, to keep them from smearing. There are several brands on the market in spray cans that use acrylic resin as the coating and benzene or other chemicals as the spray vehicle. It’s possible to make your own fixative using casein derived from milk, grain alcohol, and water that works just as well. I’ve even read reports from conservators who recommend it above acrylic sprays because it has a longer proven history of good performance. Please check my Articles page for more information on casein, and how to make your own casein solution from either raw milk or dry powder.
What you need to make casein fixative is as follows:
1 part by volume casein solution
2 parts by volume grain alcohol (aka ethyl alcohol or ethanol)
5 parts by volume (distilled) water
(Source: “The Painter’s Guide to Studio Methods and Materials.” By Reed Kay)
I recommend using a good liquid preservative* in your casein solution. Here I’ve used 2 drops of thymol in this 8 ounce mixture.
I’m using the Everclear brand of alcohol which has a high grade (95% at 190 proof) alcohol content. Any well stocked liquor store should carry it, or a similar brand.
Once you have this mixed together, you need a way to spray it on your artwork. I use a refillable sprayer made by Preval. You could also use a mouth atomizer, but they can be a little tricky to operate.
1 part by volume casein solution
2 parts by volume grain alcohol (aka ethyl alcohol or ethanol)
5 parts by volume (distilled) water
(Source: “The Painter’s Guide to Studio Methods and Materials.” By Reed Kay)
I recommend using a good liquid preservative* in your casein solution. Here I’ve used 2 drops of thymol in this 8 ounce mixture.
I’m using the Everclear brand of alcohol which has a high grade (95% at 190 proof) alcohol content. Any well stocked liquor store should carry it, or a similar brand.
Once you have this mixed together, you need a way to spray it on your artwork. I use a refillable sprayer made by Preval. You could also use a mouth atomizer, but they can be a little tricky to operate.
I’ve sprayed the sheet of clear plastic on the right with the casein fixative to show you how it turns it into a non-glossy surface.
When sprayed on paper, as I have done above, it is completely transparent, but if the paper has a glossy surface this will change it to matte. It can also easily show scratch marks, so I recommend framing the fixed art under glass or acrylic glazing. Use just 2 coats for a final fix, or a single coat if you plan to rework the art and add more coats later. I would not advise using more than 3 or 4 coats total.
When spraying white dry media such as pastels or chalk, this can cause a slight loss in brightness. When it’s first applied the pastels can seem to disappear, but will return to view in a few minutes once the fixative dries. Before spraying very powdery media like charcoal or pastel, I recommend blowing off any loose dust.
Notes: When I'm using the Preval sprayer, I stand about 2 feet from the surface, since it puts out a good strong spray. I set the artwork vertically upright, and start the spray off to one side, spray across the surface completely off the other side, and then overlap that pass slightly with another line of spray. The second coat I apply perpendicular to the first for the best coverage. It takes only a few minutes for one coat to dry, and can be done indoors without needing ventilation.
The glass jar that comes with the Preval sprayer holds @ 4 ounces of liquid. If your unit of measure in this fixative is a tablespoon, it will make about 3 ounces of fixative. You can buy extra jars from them, or perhaps find a larger jar that fits.
*Regarding use of a preservative, a reader recently brought to my attention that it isn't necessary to use a preservative here when alcohol is involved. This is correct, and if you make more casein than needed for this recipe you could keep it stored in refrigeration for several weeks, also without using a preservative. However, the main reason I recommend it is for the casein solution itself, not so much for the fixative. If you have extra casein to use later for making more fixative or some other purpose such as paint, using a preservative will allow you to keep it in storage for a long period of time, at least a year or more, without refrigeration. I've also read that it is not the oil of the preservative itself that preserves the casein, but the fumes it releases. As such, it should be possible to effectively preserve the solution just by rubbing the drop of oil inside the jar or underside of the lid, instead of actually adding it to the casein. I have yet to test this out, but I can say that a drop or two of the essential oil has no adverse affect when added to the casein.
Notes: When I'm using the Preval sprayer, I stand about 2 feet from the surface, since it puts out a good strong spray. I set the artwork vertically upright, and start the spray off to one side, spray across the surface completely off the other side, and then overlap that pass slightly with another line of spray. The second coat I apply perpendicular to the first for the best coverage. It takes only a few minutes for one coat to dry, and can be done indoors without needing ventilation.
The glass jar that comes with the Preval sprayer holds @ 4 ounces of liquid. If your unit of measure in this fixative is a tablespoon, it will make about 3 ounces of fixative. You can buy extra jars from them, or perhaps find a larger jar that fits.
*Regarding use of a preservative, a reader recently brought to my attention that it isn't necessary to use a preservative here when alcohol is involved. This is correct, and if you make more casein than needed for this recipe you could keep it stored in refrigeration for several weeks, also without using a preservative. However, the main reason I recommend it is for the casein solution itself, not so much for the fixative. If you have extra casein to use later for making more fixative or some other purpose such as paint, using a preservative will allow you to keep it in storage for a long period of time, at least a year or more, without refrigeration. I've also read that it is not the oil of the preservative itself that preserves the casein, but the fumes it releases. As such, it should be possible to effectively preserve the solution just by rubbing the drop of oil inside the jar or underside of the lid, instead of actually adding it to the casein. I have yet to test this out, but I can say that a drop or two of the essential oil has no adverse affect when added to the casein.