transmission holograms on DCG?

Colin Kaminski · Post by **Colin Kaminski** » Fri Dec 10, 2010 10:56 pm

Dinesh wrote:We've actually done a lot of transmission work on dcg. The attached picture is a rainbow of a mermaid shot on dcg (designed by Colin, actually)

I would not say "Designed". I chose the mermaid from Dinesh and Joy's box of random objects. Joy had the idea to add the coral. She assembled the model. Dinesh and Joy coated the plates. Joy set up the table while I tried to help, but was mostly in the way. The master was shot in silver. Then we changed the table to rainbow geometry and then to H2 reflection geometry. Dinesh made the exposure calculations and shot the exposures. We produced at least 8 holograms that day including the rainbow transmission hologram shown in the photo. My only contribution was to take lots of notes and to try to stay caught up with the technology as it was my first exposure to DCG and my first rainbow hologram. I still have some reflection holograms and one of the rainbow holograms from the shoot.

Thank you Dinesh and Joy.

Dinesh · Post by **Dinesh** » Mon Dec 13, 2010 9:03 pm

Actually Colin isn't telling the whole story. This is probably off-topic, but the deal was that Colin would teach me how to brew and I'd teach him to do dcg holography. My beer is now ..let's say, greatly appreciated by pro brewers as well as pro drinkers. So, I'm not sure who got the better end of the deal.
So, thanks Colin!

Tony · Post by **Tony** » Wed Dec 15, 2010 10:28 am

That is the best transmission hologram I ever seen Dinesh

Now I know what you do with the left over IPA
Brings tears to my eyes....

rzeheb · Post by **rzeheb** » Wed Dec 15, 2010 10:35 am

IPA = isopropyl alcohol

IPA = india pale ale

you pick.

Tony · Post by **Tony** » Thu Dec 16, 2010 10:21 am

I finally got a chance to read this a little more carefully.
So why wouldn't DCG be a good material to use to make transmission masters with?
If it did come out a little bit broardband but illuminated well at a single wavelenght would the rest of the freqencies result in noise? Is it becuase tuning is somewhat problematic?
I have been working on DCG masters (Dennisyuk) for a while but there are limitations. It would be great to do a good DCG master in transmission mainly because of the ability to adjust ratios. Silver works really well, but due to a lack of time, setting up for silver then converting to DCG is hard which is why I am leaning toward DCG masters.

Joe Farina · Post by **Joe Farina** » Thu Dec 16, 2010 4:17 pm

On the old forum, I posted a picture of a hologram by August Muth. I assume this was an image-planed copy, since part of the image projects. I don't know what kind of master was used, but I think it was likely DCG. Using a master/copy arrangement to enable easy adjustment of ratios is a big plus for increasing brightness. August's holograms are the brightest I've ever seen.

On the other hand, the ratios can also be adjusted by using a split beam arrangement. I've never liked image-planed holograms anyway. For one reason, they're gimmicky.

holorefugee · Post by **holorefugee** » Thu Dec 16, 2010 8:37 pm

Also, the field of view is very narrow unless you have a very large master.

Johnfp · Post by **Johnfp** » Fri Dec 17, 2010 9:01 am

I have to agree, the brightest DCG holograms I have ever made were made from transmission masters. For artsy stuff, most defects in a master are not reallized by the common viewer which to me is a great trade off for the brightness. The master does not even need to be that bright as the ratio can be adjusted in the H2 copy.

holorefugee · Post by **holorefugee** » Fri Dec 17, 2010 3:28 pm

Bright is not important but clean is really important in an H1.

Tony · Post by **Tony** » Fri Dec 17, 2010 11:40 pm

holorefugee wrote:Bright is not important but clean is really important in an H1.

I've always wondered about this.
The brightest H2 I have done are from very bright H1's
Wouldn't it stand to reason that with a brighter H1 results in higher ratios?
Why is clean better than bright?
Educate me:)