In this blog post about Indian yellow (and whether the story is true) he converts some Indian yellow watercolor into oil paint. It’s similar to what you described but using regular oil. If you skip to the updates at the bottom it’s noted that the paint took a long time to dry, which may have been because of the ingredients in the watercolor binder inhibiting drying. I would wonder if it’s possible that these extraneous ingredients could interfere with proper oil curing by reducing the cross links formed in the paint film, but it does still appear to be possible to convert watercolor into oil paint.

Hi ic.Art… for those who are new to watercolour, I recommend that they set aside the white and blacks that have been included in their various sets. There’s nothing wrong in using these colours if you understand your colour theory.

Black, used by itself is a flat and uninteresting colour. Mixed with other colours, it will dull and neutralize them. However, it can create some interesting effects if you understand how to use this colour. Practice it!

I prefer to mix my blacks. After a time, it becomes second nature and very easy to do. I will mix my blacks from the choices I’ve made for my painting. I prefer this method because it harmonizes with the colours I’ve used in my composition.

Chinese white can be used to mix tints, but they’ll appear to be opaque. If transparency is important to your work, then increasing the ratio of water to pigment is a better option. Should you try to use it for highlights, it will seem to disappear into your local colour. The white of the paper is more useful and beautiful.

If I feel it necessary to use white, I will typically reach for my gouache. It’s a very heavy body water activated pigment. It can be reactivated with water, so it’s considered a cousin of transparent watercolours. Used in conjunction with those transparent colours, if not used judiciously, it becomes very evident and unattractive.

So, my black and white watercolours are tucked away in a drawer and very seldom used.

A good point, why do manufacturers insist on putting white and black in sets?

Doug

A good point, why do manufacturers insist on putting white and black in sets?

Maybe beginners, not already knowing how they would get blacks and whites, just expect them to be there. The set then looks more complete to them.

or maybe they’ve been trying to tell us that blacks and whites are the best paints, and we should use them.

Or… they’re the cheapest to manufacture!

Chinese white is most often zinc white PW4 and the blacks most often ivory/bone black PBk9 in watersoluble binders…….so decided to grind down the pans with the tube paints mashing them into a smooth paste…….and mixed the paste with watermiscable linseed oil to make watersoluble oil paint. Am this weekend using these mixes on the grisalle (grey toned) underpainting of my next H2O oil painting. Have kept one of each water colour in case of…….??

If you’re a watercolour painter who does not use these colours, what do you do with those black and white watercolour paints that find their way into your colour collections?

Without cleaning of pigments from watercolor vehicle it’s not a good idea at all to use those paints in mix with linseed oil, layers would crack and very probably ruin your paintings. Since zinc white and carbon blacks are cheap and widely-available pigments, if you wish to make your own oil paint with them, it would be easier to buy them as raw dry powders than to wash all the watercolor vehicle out of them. It’s not unrealistic, but hard to do.

Maybe it’s an opportunity for you to try something new? In the past, zinc white was used by watercolorists as a first layer to make some parts of their paintings such as faces or figures more accented. On some papers like non-bleached Saunders Waterford the effect will be quite visible.

My suspicion is that the contents of many of the paint sets are based on what doesn’t sell as individual paints.

As for what to do with black and white, my suggestion is to give them to a school teacher for her elementary school art classes.

Sling paint,
Virgil

I whole heartedly agree. No need for whites or blacks.

Tom

Why?
Because they are broader minded on watercolor painting
That is very valid to use both black and white

Use them both as mixers
White enters into the old and classic world of bodycolor
Black works very well to break colors and increase the tone

I wonder why they added white to the cotman sketcher’s set, but not black. Is white more useful than black generally?