Acetate Gobo - Pacific Lantern

[Rory]

My lighting designer has decided that he wants to use acetate to make a specific gobo for a pacific lantern, however I have a few concerns.

 

1. would the acetate not warp under the heat?

2. would the ink not run under the lantern strength

3. Does acetate act like a frost under light?

4. does anyone know what size I should make the gobo to get it to project correctly, keeping in mind that it'll probably be projected over 7 metres or so.

 

I understand that these are all simple things, however I'm hoping someone might know some info about it all, thanks.

 

R. Kay

[jayselway]

I would have thought that depending on the acetate, it might actually melt / burn. I saw someone make an acetate gobo a while ago, with a stanley and a laser printer. The ink ran really badly, and within half an hour the acetate was a lump of goo in the base of the lantern. Personally from seeing this, I really wouldn't recommend it, unless you can get some acetate which can deal with the heat produced by a lantern.

 

Acetate which is completely clear wouldn't act like frost (think OHP), but printing onto this would be more difficult, cause the ink might run before ti even gets to being cut!

[niclights]

'Acetate' :huh:

 

Not only would it melt but I see no way you could get anything on it that would be opaque enough.

 

The gobo should either be metal or dichroic glass.

[paulears]

One of the sales claims of the pacific is the ability to use acetate to print your own custom gobos. There is a thread here

and the selecon site says this:

 

What are the advantages?

• Cool operating controls (lens, focus knobs, lamp peak/flat adjustment, shutters) even after hours of continuous use.

 

• A gate so cool you can use plastic images printed on transparency film with selected light sources.

[mikienorth]

According to the selecon website, the use of plastic images in a pacific is fine, as long as certain resrictions are adhered to. I have, and others on here must have seen selecon demonstrating exactly this at the ABTT.

 

The LD will have seen this and want to try it, if not already has. As long as the correct lamp back is being used with the pacific, as the link shows, then there should not be an issue.

 

I haven't done it myself, but as long as you are careful it should be fine.

[niclights]

Wow. Just read that too. Learned something today :huh:

[jayselway]

Every day's a School Day! Even Friday afternoons! :huh:

[the kid]

We have done it before. Several times in-fact, it does work very well and as the site says run at 60-70% and they will be fine.

 

We often use black and white photocopy's on acetate.

[Neil Hampson]

I used 6 Pacifics earlier this year for this for a large dance show. I was a bit nervous of the idea at first but was very impressed by the results, however from experience a few pointers;

 

When the website says 80% intensity it does mean 80%, not 81! ( I tried various intensities using the RFU, standing over the lantern, at 80% all was fine for hours, at 82% the thing was almost in flames!)

 

When I did this I did not use the proper Pacific Acetate gobo holder that clamps the edges of the gobo, I used a bog standard gobo holder. This meant that the acetate did wrinkle up a little but on the whole it was not too bad.

 

You must use the gobo slot furthest from the lamp housing (obvious when you think about it, but I didn't)

 

I would recommend getting a few copies of the image made up and swap them out every few days.

 

Next time I would also hire extra gobo holders and put heat shield in the front slot.

 

When making up the image, try to use bold colours, the colours from the laserjet, although quite good, seem to come out a little greyer when projected. Also remember if you are using black for large portions of the gobo, the toner will not block out all of the light, and Will project a dark grey. you may need to use a tin foil gobo as well if this is an issue.

 

The acetate was printed in colour on a laserjet onto an A size gobo for the standard 26-? pacific

 

The image I projected was onto the full Cyc, at over 12m wide, shuttered down to fit the rectangle, projected from around 15-20m away on the circle front.

 

Considering this is was standard unit (800W) I was impressed by the throw and colour of the projection, even at 80%

 

If you look half way down on this page:Kate Simmons there was a few photos of the show, (Bear in mind the photo's were of the Performers not the lighting) look for Kate Simmons 'Interchange' I think the photos are rotated every so often on the site, at the moment there is only one photo (and the projection is deliberately way off focus) and is not a great example. I'll have a look to see if I can get any more, better pictures.

 

If you need any more info P.M. me

 

Wow 5 posts in the time it took to type this! - Must type faster

[Dmills]

Setting the lamp to a slightly over flat field helps as well.

 

Do make sure you get laser printer transparencies, the ones for ink jets have a tendency not to be heat proof!

 

Regards, Dan.

[sparkyweb]

You will need to make sure that the lantern is set to "flat" as mentioned above and that you use the 600W lampbase only. It will also help considerably if you use the gobo holder that has the heatshield in place.

 

You can also use a Rosco Image Pro and run the lantern hotter or more "peaky" as the Image pro has a fan in as well as the heatshield.

 

I have had customers take the lantern away on a 6 week tour using only one acetate gobo- so it is possible.

[Neil Hampson]

IIRC the rosco website also states that you can use the image pro with a source4 as well. I've never tried it and I'm pretty sure that ETC have never condoned the use of them.

Assuming that you already have, or are already hiring a Pacific, is the additional cost of the ImagePro going a bit far? unless you really need the extra brightness offered by the Source4. when I enquired the unit was about £30 to hire and the blank slides were £25 each.

 

Using the pacifics is cheap enough to be able to get a few gobos made up and play around, you can get 5-6 A size on an A4 transparency and our local cpy shop will do colour laser prints onto Acetate at about 80 a sheet (including the acetate) just make sure you ask for high temp.

[MarcT]

The Rosco ImagePro is excellent. I've used it both Pacific & Source 4 zoom profiles.

In the case of the S4, only a 575W lamp can be used.

 

When using an iPro, you *must* print on an inkjet - laser toner detaches from the acetate when it gets warm. Especially important if you're using it in an S4.

 

The iPro blank slides are a bit pricey, and can only be used once - so they say... :huh: There is an artwork creation guide in pdf format on the above site.

 

If you've got "black" printed areas around your artwork, just use the lantern shutters to mask off the edges.

 

Have fun!

Marc

[StevieR]

Yes, acetate gobos in Pacifics work.

 

Don't use lamp powers over 600w, use the selecon gobo holder, screw the lamp base right down and run it at 80% and it should be fine.

 

If you are planning to run the effect for any length of time or for more than a few days then I would advise getting a Rosco Imagepro which will fit in both Pacifics and Source4's.

 

And finally, the image quality and colour saturation possible on acetate is no where near that of a glass gobo. If you need a good image with strong colours then get a glass gobo done.

 

Steve

[GridGirl]

I've used acetates in 1kw Pacifics and though I usually burn through about 3 gobos while focusing and peaking the lamp correctly, once you've got it right it works beautifully. I've used them on a ten-week season, with relatively heavy usage during the show, and I think I replaced the acetates maybe twice over the run - if you treat them nicely, they'll last longer than you think.