Size is everything!

I have spent the best part of a week experimenting with the Salt Printing process using Strathmore 400, Fabriano Artistico 5 and Canson XL Watercolour papers. The one thing I found in order to get borderline consistent results, each one of these papers needs to be sized. To size the paper mix 2 grams normal household gelatine in 20ml of distilled water. Once the gelatine has 'bloomed' a little (circa 10min) add enough water to make 100ml of gelatin solution and then heat the gelatine softly making sure to keep the temperature of the solution between 40°C and 50°C stir for a while until all the gelatine has dissolved. 

To apply the gelatine to the paper you need to have the 2% gelatine solution quite warm if it goes cold it will become not suprisingly gelatinous and impossible to apply. 

Pour 2/3ml of the warmed 2% gelatine solution on a saucer and with a foam brush apply it to your watercolour paper, first going length ways across the paper then width ways to make sure you have an even coating. 

Once coated leave it to dry for at least 1 hour on a flat surface before applying any sensitizers. 

Sizing helps prevent sensitizers from pooling in the drying process which will lead to blotchy prints. It also increase contrast in alternative (historical) photographic processes by not allowing sensitizer solutions to absorb all the way into or through the paper leading to dull, soft low contrast images. 

I have found when make salt prints it's essential to size papers and the only time I have had decent results with salt printing is when the paper was sized. Whether making a Cyanotype, Argyrotype, Van Dyke Brown etc... I will size each sheet before applying any chemistry to the paper from now on. 

Happy printing.