Here is a sample from my lab notebook…
Today is mirror day!
1) Check fit of slide in 35 mm
2) Do “sheeting test” on unwashed slide
3) Make mirror slides
4) Test drying slides
5) Examine polish
6) “Water Polish” with cotton ball
7) Dry polish with Lampblack
8) Put in fixer for 10 minutes
9) Heat with fixer to simulate gilding
Castle Temp = 55.7 degF @ 8:30 AM
1) Slide seemed to fit just fine. Could not see any “bulge” when I shut the film loading door. Slide lines up easily on the film guides. I did note that the first slide had a spot of contamination. Note – shop for a diamond or carbide tip glass cutter to cut slides in half.
Other observations-A good place to line up the slide for consistency is along the bottom bare metal film guide and on the right “edge” of the film frame support platform. This centers the slide with 2 cm of “waste glass” on either side of the shutter opening.
2) Slide passes the water sheeting test. The water doesn’t all “slide off” but it doesn’t seem to bead up anywhere.
Castle Temp = 60.1 degF @ 9:15 AM
Took a quick break to fix broken ring flash and repair sealing surface on distilled water spray bottle.
—-Delete – lab glassware price list —-
Spent quite a long time setting up table saw with 80 tooth plastic cutting blade. Cutting plastic supports for small tray and setting up glass mirroring chemicals for the first time.
3) Made three mirror slides. 15 ml silvering solution was too much. (note tin solution can last 5-6 hours, but silvering solution has to be used up immediately) Will have to inspect slides before using. In spite of being advertised as “pre-cleaned” one had a piece of dirt that blocked the mirroring. A single pass of the solution left a very thin mirror layer. Cotton ball and cotton round scratched the silver layer (wet or dry)
4) Standing slides on end and drying with heat gun on low setting held 10-12 inches away seemed to work pretty well.
5) Looking for ways to remove residue left by mirroring solution. A) NuShine II S strips silver off immediately. No Go. B) What seems to work best is dry polishing with lampblack and a microfiber cloth using very light finger pressure. This is going to take some experimentation. I may write to the Angel Gilding people and ask what the residue is. The mirror looks very fine however with only a little polishing.
6) Water Polish – no go, see above.
7) This was good (Lampblack) see above.
8) Put in fixer A) Ammonium Thiosulphate – silver took on a “frosted appearance” in places right away. Then the silver started separating from the glass. (I only had Ilford Rapid Fix. I will have to get some Sodium Thiosulphate and see if it is any less destructive). B) Strong salt solution – even worse than the thiosulphate. As soon as a single drop hit the slide it frosted over and little bits of silver floated away from the glass until it was perfectly clear. It left a perfect round circle of bare glass.
9) Since fixer is no-go, I just heated the slide over the alcohol lamp bare and then with water. Bare (air exposed) heating damages the silver making it appear powdery white. Heating with water seems to have no deleterious effect. Was able to get water bubbling and slide too hot to hold. Silver stayed bright, shiny and intact.
Final experiment. Made 5 more mirrors. Wiped slides w/ dry paper towel, puffed w/ air and wetted on rack with distilled. Tin 30 sec per procedure, then silvered twice for 5 min each. 12 ml solution x2 (4+4+4) was able to mirror five slides fully with a small amount left over. Double silvering made a much more even and opaque covering layer.
I will have to try the silvering solution on bare copper.