Re: Alt print on Glass?
Hoo boy, Jack is not an expert . . but, an interesting thing about the
acid is that it can be used two ways. One as a gas and another
as a liquid. I'd absolutely state you should have aid when working
with it as a gas. You know, there are specialized shops for such
things. When used as a gas it'll make the glass opaque and when you
dip it in the liquid it etches but 'cut' is clear.
Such things as drawings are done on glass by, say, taking a flat sheet
of glass and covering, or soaking it (so to speak) in wax. Then
with a sharp tool cut away the was. Then immerse it and where the
'drawing' was, that area will be etched or cut. You then remove
the wax.
There are also products you can buy where you create a sort of
photographic decal and then as I remember, use hot water to wash
away the portion not hardened . . . then you sand blast you photograph
onto glass or granite. This stuff can be found in the tombstone
business area.
Jack F
On May 18, 2009, at 9:04 PM, Jacek Gonsalves wrote:
Thanks for the advice Jack. Will also look into hydrofluoric acid.
The final and ultimately idea is to have the most transparent layer
for a highlight without any visual etching. If the etching or
grittiness is extremely slight to the eye then its ok. I would end
up lighting the back of the glass print mainly from 45 degree.
Jacek
Quoting jefulton1 <jefulton1@comcast.net>:
Carborundum is very hard and used for grinding tough stuff. You can
buy
a carborundum block to aid in the
sharpening of knives and it comes in various grits.
A quality sandpaper of fine (600 or slightly less) grit like that
in a
wet-or-dry type can give a slight texture
to glass. I use a grittier version to sand the edges of glass cut for
framing photographs.
Also, you can purchase hydrofluoric acid (of course wear gloves and
eye
protection as well as a high quality
mask if you work indoors) to etch glass.
Jack F
On May 18, 2009, at 8:30 PM, Jacek Gonsalves wrote:
Hi Tom,
Thanks for the information. Can you elaborate more on
carborundum? Is there a specific product I can get? Is it this by
any chance?
http://www.hoskindiamond.com.au/prod2016.htm
Ammonium to clean glass, will try some Windex, that i'm sure has
ammonia in it ! :)
Ta
Jacek
Quoting Tom Sobota <tom@sobota.net>:
Jacek,
Printing on glass is not very difficult but the exact procedure
depends
on the process.
I have made three-color gums on glass, but gum doesn't stick very
well
on plain glass, so I first 'frosted' the glass surface with
carborundum. Well, actually a valve-polishing compound that has
carborundum.
I use carborundum because just 'sanding' the glass is, in my
experience, very slow.
On the other hand, gelatin sticks to clean plain glass very well,
so
any gelatin based process such as carbon works very well without
the
need of any additional substrate. But the glass has to be VERY
clean,
and that means at least some ammonia-based detergent. You could
also
consult instructions for preparing glass for collodion. Glass is
notoriously difficult to clean well :-)
For maximum adherence of gelatin you could use some sodium silicate
substrate as used for collotype. However, for a quick test a
reasonably
clean glass will do.
You don't need to brush the gelatin on the glass. Just flow it
from a
flask, and help to spread it with a finger (or a glass rod). The
gelatin will dry to a nice transparent thin coat. Keep the glass
warm
while spreading, and then cool it on a very level surface.
cheers
Tom Sobota
Madrid, Spain