Last month, I field-tested Gamblin's new medium: Solvent-free Gel, during my trip to Kauai.
The flash point of the solvent-free gel is high, so it can fly! Time to test it on a trip. The tube is great: it fits right in the box with the paints. Don't have to worry about getting that last bit of gel out of the nasty bottle.
The gel allowed my paints to move easily across the canvas, without dragging on underneath layers that had already become tacky. This is important to me because my painting style is to push color into color. Most alkyds, even gels, become tacky within twenty minutes of hitting the canvas (possibly because of solvent evaporation) making it hard to continue pushing the paint around. The drying oils I've used do not become tacky. In this respect, the Solvent-Free Gel is more like using linseed or safflower oil.
I'm sure Gamblin can tell you a lot more about the drying time of this medium. For my practical purposes, paintings left in my room (80-85 degrees and humid) dried in 2 days. Paintings placed in the car (90 degrees plus) dried in 1 day, with a few extra hours needed for very thick yellows.
This medium appears to be just a little glossier than Neo Megilp, and a little less glossy that Gamblin Gel. A little glossier than I am used to, but within an okay range. My dry paintings didn't dull down from drying in.
Putting a dab out on the palette: This worked great for picking up a little medium to mix in with colors. The gel stays put, even on a steeply angled palette. No need for cups or containers.
Whipping some medium in with the white: I used a small amount of medium, maybe 10 percent of the mix. I like this method because it distributes the medium pretty evenly in with some of the slowest drying colors. I may even try whipping some into my Indian yellow and sap green. I can also see whipping some into any colors that have gotten stiff at the end of the tube due to oil separation. The disadvantage is that any leftover color on the palette will skin over pretty fast if you don't get your palette into the freezer.
Brush cleaning: Using the medium as a brush cleaner during the painting session worked great. I didn't have to worry if any bits of leftover medium got into the paint mixes. After each painting session, I cleaned brushes with mineral oil so they didn't turn into solid sticks. After the trip, I cleaned them with soap and water as well.
I love this medium. It fits the way that I paint, and the paintings come out with just the right amount of subtle gloss.