The topic of film squeegeeing comes up fairly regularly on the holography forum and I’ve been meaning to write up a method that I use with good success.
Read on for more info…
If memory serves (and sometimes it doesn’t, so have some salt) the idea for using glass came to me from Jonathan Head. I’ve been using it for about a year and a half so the source is misty.
What I’ll be showing is the method I use for squeegeeing just after soaking my film in a TEA bath. I use the same basic methods for the final post-rinse squeegee.
At any rate, I start with the the film in the TEA bath (pretend this is all being done under dim lighting) and the processing table laid out with my squeegee glass. The glass has had four anti-skid pads glued to the bottom so it won’t slide across the table. Note that for clarity I’ve put paper towels underneath the glass. Usually I roll up a paper towel and only put it under the right-hand edge to catch the excess water as I squeegee.
Take the film out of the bath and place it emulsion up on the glass. I use tongs that I purchased at a local electronics shop. I coated the tips with the liquid rubber used to insulate tool handles.
That coating provides a good chemical resistant grip without scratching the film.
While wearing a rubber glove (you only need one), hold down one corner of the film and pass the squeegee over the film. You’ll need to practice this in full light a few times to get the hang of how much pressure to use and how fast to move the squeegee. Btw, I just use the squeegees sold locally in the grocery store. They work great for the size film I use (typically 4×6" or 5×7").
Now dab the finger that had been holding the film on a paper towel (to dry it) and gently wipe that corner of the film with the towel (also to dry it). Hold down the film again and gently wipe the surface of the film to get any excess moisture off. There tends to be some near the edges because of the liquid squirting out from between the glass and film. I prefer to use the paper towel rather than squeegee multiple times.
Oh, one other thing. Use fresh clean paper towels and don’t let them get soggy.
Now carefully insert a fingernail under one corner and gently lift off the film.
Unfortunately I didn’t get a picture of this, but while holding the film off the glass, give the glass a couple of squeegee passes to remove the water left behind.
Now place the film face down on the glass.
And squeegee the emulsion side *once*
Lift up the film again and while holding the edges carefully wipe off any excess moisture from the *non emulsion* side with a clean, dry paper towel. Believe me, there will be some moisture left over.
Now set the film aside to dry or if you’re in a hurry you can dry it with a hair dryer, just remember to aim the dryer at the non-emulsion side of the film (or plate) so that it doesn’t dry from the outside-in and trap excess moisture in the emulsion.
Before you leave the table, clean the glass with windex and don’t forget to get under the right-hand edge where the soaker towel was sitting. You want to keep this surface as clean as possible or you won’t get good or consistent results.