Varnishing prints is tough.
Especially when you are just getting started.
It seems like everyone has to make a few mistakes first until they settle into their own groove. Call them growing pains. We’ve all been there.
Here are the solutions to 5 common print varnish problems.
1. Bubbles or pinholes in varnish
Don’t worry, it’s fixable! Bubbles and pinholes are commonly caused by one of two things:
Applying too much varnish
Since canvas needs to absorb coating evenly, too much coating creates air pockets in the weave of the canvas. When the air tries to escape, it pushes itself out either partially (which looks like air bubbles) or completely (which look like tiny pin pricks or pinholes, see the above image).
Not letting the print dry fully before coating
I know, I know – you want to get these prints coated and sold ASAP so you can keep the biz cranking. Don’t make this mistake and have to reprint. It’ll hurt you in the long run. The canvas needs to go through a drying process–commonly referred to by us print nerds as “outgassing”–before it is coated, otherwise bubbles and pinholes can appear as the process continues to happen with coating on top of the print.
Give the print 24 hours to dry before applying varnish. This can vary, especially if you are in a very humid climate where drying can take twice as long or even more. If this is the case, you might want to look into putting a dehumidifier in your coating area to get the relative humidity around 45%.
2. Ink coming up on the roller when varnishing
Ink uptake during roll coating is almost always caused by either an incorrect printer setting, or trying to coat the canvas too soon after printing and before it’s had the time to dry. (See my above point about being patient to avoid a reprint!)
For the print setting, make sure you’re selecting the correct media type setting in the printer driver. If you are selecting one that uses too much ink for the paper or canvas you are printing on, it may take an excessive amount of time to dry, thus leading to ink coming up on your roller during varnish application. Messy.
3. Streaks, lines, roller marks, or runny varnish on print
All of these problems are usually simple, common mistakes during the varnish application process. Personally, I’d say that applying varnish to a print is the most difficult step in the printmaking process (hence this article!) and there is certainly a learning curve to be navigated before you become a varnish ninja.
Things like pressure on the roller, speed, amount of varnish, spray gun settings, dilution ratio of the varnish, hand speed, distance from the print, and more all come in to play when trying to get that “perfect print” (it CAN be done!) There are so many little tips and trick for each method that we have dedicated articles for each. They’re really helpful, so check them out if you just can’t get the hang of it. See how to become a spray ninja.
4. Prints look cloudy or milky
If you’ve ever seen a kind of milky haze over your print after it has had the chance to dry, you’ve likely applied too much varnish at once. When this happens, the varnish is unable to dry evenly, leaving a cloudy appearance.
I recommend using about 1/2 ounce of varnish per square foot of your print. If you are spray coating, it’s going to be more about the hand speed of your spray gun hand, and the consistency of the varnish exiting the gun (see the detailed article on how to spray canvas varnish here.)
5. Canvas is cracking
You will usually experience cracking (commonly called micro cracking or edge cracking) on the edge of the print as it wraps and stretches around the stretcher bar.
This canvas cracking is usually caused by not applying enough varnish. As a rule of thumb, you want to apply a medium coat, let the print dry to the touch, then apply another medium coat.
As I mentioned above, I recommend about 1/2 ounce of varnish per square foot of your print, per coat. For example, a 24″x36″ print (6 square feet) would need about 3 ounces of varnish per coat.
What did we learn?
Varnishing isn’t easy! There are a number of seemingly small details that may be just slightly off. Small details, BIG frustration!
Undoubtedly there are issues that we didn’t cover here. Feel free to leave a comment and we’d be happy to help out.
Who said nothing in life comes free?