This is cool!! Thanks.Originally Posted by Ron in Arcata California
This is cool!! Thanks.
Lachlan.
You miss 100% of the shots you never take. -- Wayne Gretzky
That looks very like Deardorf ground glass. I imagine to make them they had a grid, heated yellow hot and then placed in contact with the glass.
Darkroom Automation / Cleveland Engineering Design, LLC
f-Stop Timers & Enlarging meters http://www.darkroomautomation.com/da-main.htm
Did you ever dial in the laser ground glass? I would be interested to know if it was worth pursuing. I have access to an 80w laser engraver and I attempted a few tests on some big box store glass. The etching in my tests was a little on the heavy side, even at the lowest laser power/ fastest speeds (this could be due to an aging laser tube).
I hope you understand that I was using the laser to make the lines, not the frosted glass. I haven't done anymore experiments but it looked promising. Personally I just use a pencil because I can erase it and that's all I need. Lasers are fun though.
Great idea, Ron. There's a laser engraver at the local library that I can use.
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
Some of the Deardorff lines will wash off with soap and water. I have also read that the clear lines might be lacquer. I suppose there might have been different methods over the history of the company.
Sinar lines will easily wash off...don't ask how I know....
“You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
― Alexander Den Heijer, Nothing You Don't Already Know
I've done a lot of "permanent" marking on low friction surfaces, from parts that see a great deal of wear from use, to parts that are seen but never touched. For both metal and glass I usually use a combination of an etch filled or topped with a paint. Obviously glass can't be as deeply etched as metal can be but the idea is to abrade the low friction surface to aide adhesion for greater durability of the markings.
For glass I've found a chemical etch followed up with a black nail polish lightly rubbed into the etched area yields light fine lines that look almost like pencil lines. Darker lines can easily be achieved by stenciling a thicker layer of paint over the etched areas as well but there is more work and risk to the process.
There are many ways to make a stencil to outline the areas to be etched and then painted so I wont try to outline them, but rather I'll say what has worked well for me in the past and what should be a process any photographer can follow; a photoresist stencil.
Film resists may be easier for most people, but I use a liquid photoresist since I can obtain a thicker film slows the diffusion of the etchant into the photoresist. During long etching times hydrofluoric acid diffusion into the resist can can the resist to peel around the etched areas. I avoid this by using a built up resist layer than found on most films.
After scrupulously cleaning the glass surface I apply a thin uniform layer of liquid photoresist. This process the same used for inking relief type printing plates, using a rubber brayer and a second plate I roll out the photoresist so that I can transfer a thin layer to the substrate. The result is a thin smooth resist that will contact the stencil without gaps. I set the coated plate in a lightproof box to dry for a day or so.
I use adobe illustrator or a cad program to design artwork and then print to create my negative on pictorico film. I then contact print as I normally would (heavy glass over the negative/ plate sandwich exposed under UV light for about 45 seconds). I develop the photoresist, dry it and re-expose it for about 10 minutes to further harden the resist. The plate is now ready to etch.
I brush glass etching cream aka hydrofluoric acid over the open areas in the resist and leave it for the length of time recommended by the manufacturer. which is usually around 10 minutes. Most photoresists are not degraded by hydrofluoric acid, but the resist can still be undercut at the edges by over etching the substrate. I wash off the etching cream in cold running water bath, then rinse and dry the plate with the intact resist.
The next step depends on a number of factors such as the developer/stripper for your resist and the paint you wish to use. If they are incompatible the stripping may also remove your paint so careful reading of data sheets or experimentation is encouraged.
I've had some success with solvent based paint applied carefully to the open etched areas with a cotton swab so that there is not too much overlap onto the resist. Beware, if you spray the entire plate the paint prevents the stripper from contacting the emulsion and you will need to scrape everything off to salvage the plate.
I strip the resist using hot water and the stripper solution, and I use a scalpel to tease the resist away at the paint edges. But for the most part I just prefer to rub paint into the etched areas after stripping the resist. In those cases I etch longer to get slightly deeper etch.
I've used various paints from solvent based spray paints (sprayed onto cotton swab to use as brush) to acrylic enamel or acrylic ceramic paints designed to adhere to low friction surface like glass and ceramic.
Also I have seen a new product I may try as well, it is a sheet of unmounted silk screen material pre-coated with photo emulsion that is designed to be exposed and developed and then used as a stencil.
4x5 size:
https://www.ezscreenprint.com/produc...-mini-stencils
It should work for applying both the etching cream and the final paint. Both should be tested first to ensure they're viscose enough.
The potential down side is that the stencil is not adhered to the substrate but merely taped at the edges, so there is a potential for the cream or paint that is too thin to smear via capillary action between stencil and plate.
The upside is that the stencil is not affixed to the substrate so that the stencil can be removed, cleansed of the etchant and then dried and the substrate cleaned, dried and readied for an application of any paint viscose enough to squeegee thru the stencil.
The only potentially difficult thing is to ensure the registration of the stencil prior to the paint application. The result should be thick dark painted fine lines that are far less likely to wash or wear off.
Make, draw, an overlay transparency on a sheet of polyester film and a fine alcohol pen. Then you can make a few different ones, as one with the Fibonacci spiral.
An other way is to photograph, on a sheet of (graphic-) film, any pattern you want and reverse develop it, and use this as an overlay.
BTW, put the overlay on the viewing side of the ground glass, not the lens's side...
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