Re: Introductions
Posted: Tue Feb 02, 2016 6:43 pm
And a lot of students learned from these: http://edweslystudio.com/Pedagogy/PedagogyFrameset.html
A place to discuss holography
https://holowiki.org/forum/
Start with silver halide. No kidding.hologram wrote:and it's just a matter of time until i'm pleading for help with my DCG holograms
why do you say that? i wanted to start with DCG because i didn't like the idea of having to buy film. DCG seems like it's dirt cheap, doesn't have to be ordered from special suppliers and also produces brighter holograms. i'm fine with initial failure as long as i'm not wasting expensive film.lobaz wrote:Start with silver halide. No kidding.hologram wrote:and it's just a matter of time until i'm pleading for help with my DCG holograms
i bought a 100mw microgreen from holomaker, so it is SLM. although he recommends that it isn't run at full power continuously, so at least 50mW. maybe more, i have no experience with these lasers. anybody have a microgreen from holomaker? if so i'd be interested to hear how they use it for holography.admin_jsfisher wrote:What sort of green laser? A 100 - 150 mW diode module from eBay is unlikely to work very well.
lobaz wrote:Start with silver halide. No kidding.
I suppose you did not make any hologram yet. First thing to learn: when making a hologram, anything can go wrong **very** easily. Holography is very sensitive, but until you try it, you have no idea how bloody sensitive it is.hologram wrote:why do you say that? i wanted to start with DCG because i didn't like the idea of having to buy film.
No problem here, there are plates sensitive to green as well. You can try Harman HoloFX Green (available from Harman eshop), Slavich VRP-M (available e.g. from Integraf together with chemistry) or Ultimate U08 Green (available from Ultimate eshop together with chemistry). Trust me: order a few plates for first experiments and proceed step by step.hologram wrote:i've also invested in a green laser so it's probably too late to go back, haha
You can use 50 mW for small plates. Doubling exposure time is tricky: longer exposure increases chance that something moves, air circulation affects the hologram, laser must keep its properties twice as long... I don't make DCG, so maybe I am wrong with this one, but at least in silver halide the law of reciprocity holds just for short exposures (i.e. 100 mW for 1 s equals to 50 mW for 2 s); for longer exposures (minutes), you must use even longer exposure than predicted by the law.hologram wrote:is 50mW decent for DCG? would doubling the exposure time give me the same result as a 100mW laser?
It is definitely possible if your concrete floor is still enough (read: in the basement, no traffic in the neighborhood, no air currents). Remember that even your presence in the room makes air circulate! If you breathe, it is even worse. For first experiments, glue everything together. If you succeed, slowly relax, e.g. glue almost everythinghologram wrote:made denisyuks on a concrete floor
That's the biggest trouble: a beginner rarely achieves a marginal success. You either succeed (i.e. you have a hologram), or end with a blank plate. Nothing in between.hologram wrote:even marginal success is motivation enough for me
Under no circumstances let anything from you holography work area into your kitchen...not even your kitchen sink, especially not your kitchen sink.Chemical safety is always important. In DCG-based holography, the gelatin and water used are completely safe; isopropyl alcohol and dichromates are not. Alcohol is highly flammable, especially at the higher concentrations used in drying a hologram; dichromate is a strong skin irritant and a known carcinogen. Treat them both with the respect they deserve.