White spots have become an ever-increasing issue when making Bromoil prints, and this is not limited to one paper manufacturer. This is how you solve it.
Papers used for bromoil: Foma 112 & 113 & Other Papers
The problem seems to have increased over recent years and is not limited to one manufacturer. For example, older manufactured papers worked fine with the Bromoil process. However, recently manufactured papers of the exact type and make exhibit white spots upon inking. I now firmly believe that the base paper has changed in some way or other.
“The white spots are caused by water ingress through the back of the paper. I discovered this by viewing a partially inked matrix under high magnification, on a light box.”
There were the usual large white blemishes with central pin-pricks of light showing through. I couldn’t tell if the pin-prick was in the emulsion or the backing paper, so I peeled off the emulsion and viewed it again. It became evident that the fault lay in the backing paper. The cure was very simple, which was to use a sealant on the back of the matrix.
Recommended method for fixing white spots on bromoil prints
- Flatten the dry matrix by dampening the back and placing between 2 sheets of clean paper. Then place some heavy books on the top and leave for a couple of days. This step is important as you don’t want to seal any buckles or curves into the paper.
- Coat the back of the now dry and flat matrix with 2 coats of either Gesso or Liquitex (either work well). Ensure each coat is fully dry before proceeding.
- You can now complete the Bromoil in the normal way.
- I would recommend that you take the completed and still damp print, sandwich between 2 clean sheets of paper, as before, and press with books.
- After flattening is complete, the print can be stored or mounted, as desired.
I’m not a lith printer but I know they have been having similar issues with some papers. I wonder if coating in this way would work for them?