infrared film and pressure plates

[jim kirk jr.]

Here is my dilemma,

My Cameras(35mm) have pressure plates with holes cut out for date imprinting,which I don't have anyway.With any lens in my possession at their
widest angle and with an 89b filter and above the negatives and print get a ghost image from the cut-out.Obviosly this is a result of the nanometer cut off from the filter(#29 and #25 red do not cause this)and in an attempt to rectify the situation I've placed aluminium foil with electrical tape on the back of the camera,to no avail.Short of buying new cameras(not an option at the moment)or new pressure plates is there any other option.Other than that there has been no other issues with regards to infrared film.

Thank you to anyone who can help.
Jim

 

[David R Munson]

Well, what kind of camera do you have?

 

[glbeas]

Best cure for this is to tape a piece of black paper backing from a 120 roll of film onto the pressure plate. Be sure the tape doesn't hang on the film path.

 

[jim kirk jr.]

Cameras are Canon Elan 7,no issues with fogging(maco 820)and this is the film in question.
I've had great success with the film ,even with an 89b filter-the ghost image occurs mainly with flat areas of even tone.Usually I use a #29-Less IR effect but sometimes,especially with contrast,less works best.

 

[jim kirk jr.]

Thanks Gary,
I'll give it a try-I did try to tape a piece of developed film to it but Maco film seems to be thicker than most films and did not fare to well.

Jim

 

[David R Munson]

Next question - can you buy replacement backs for that camera?

 

[jim kirk jr.]

It's a possibility that I could,I'd imagine canon makes them and was being "cost-effective" by putting the plates with holes in cameras with no date imprinter.Thanks Dave,I'll check into that suggestion as well-although I'm going to try Gary's idea first.

 

[glbeas]

Some folks have also used a piece of aluminum foil on the back to enhance the halo effect. Important point in this is to have the same reflectivity across the entire pressure plate. Either way will eliminate the ghost images from the data port.I doubt you would want to put another back on the camera, wouldn't be cost effective. If you are going to dedicate the camera to doing infrared though you might look into a between the film rail filter so you can see to focus with a visually opaque filter.

 

[jim kirk jr.]

Thanks for the info-would I put the foil on the back of the plate and if so would that stop the ghost image or do you mean put the foil on the front of the plate in contact with the film instead of 120 black paper?I've ben a dedicated infrared user(sometimes near infrared ,konica750,maco cube 400 plus and ilford sfx)for over a year now and usually i just focus first then screw in the filter.I tried a "pro-grain" filter(inside the camera)and discovered that no matter how clean I thought things were,they were not.
Is dust attraction an issue with those filters?

jim

 

[glbeas]

The foil would be used instead of the black paper. Sadly dust is prone on mylar in a dry climate from static charges. A polonium brush like used in the darkroom may help.
Actually the best system I ever used for IR was the twinlens MF, with the IR filter on the taking lens you can still see to focus.

BTW what is a "Pro Grain" filter?
Are you familiar with WJs page and the Infrared mailinglist?
http://www.a1.nl/phomepag/markerink/mainpage.htm

 

[jim kirk jr.]

Gary,
Thanks for the info-I'm going to try it this week.I've seen WJs homepage but am not on the mailing list.The pro grain filter(actually there are two:course and medium that come in one package)is made by sunpack,I believe but is availible from B&H photo-the only place I've seen it.They go inside the camera between the shutter and the film and depending upon which one you use you get acertain amount of grain on your negs,prints.The problems are,dust-If any dust,even the smallest particle is on it then the dust spot will appear on every photo in the roll so unless you use a black bag to remove it your also geting grain with each photo.Also it would appear,at least with IR film(I did not use them with regular bw film)that they are very inforgiving of exposure.The more you overexpose the neg-well lets just say it disapates the entire image,so you need to be exact with exposure.The only other issue is not poking it through the shutter(a warning on the label)but I saw no real concern.

JIM

 

[glbeas]

I would think it easier to add the pseudo grain when making the print, as well you would have an unaltered neg to use in other ways too.

WJ recommends a polyester filter between the rails for opaque filters to uncomplicate the shooting and speed up the process. You can see to focus and shoot immediately and you can use any lens you have without having to buy new filters or adapt one size to another. Makes a big difference to him as he takes his camera along on backpack ski trips where fiddling with a filter while shooting can be a very big chore. Its really valuable for wide angle lenses that tend to vignette with any filter in the way.
That said I don't have that because I haven't figured out how to do it with a Bronica SQAi. I will sooner or later but now I get satisfactory results with a 29 red filter.

 

[jim kirk jr.]

After my first two attempts(one for each grain filter)I gave up-realizing as you've pointed out that there are better ways,but hey I'll give most anything a chance at least once.I'll have to look into the poly filter-it would be easier-it is a bear screwing on a filter with fingerless gloves in ten degree weather.I find the 29 red to be good in most situations also,but with maco 820c and konica if the weather is overcast or cloudy with little to no sun I find the best negs come from the 89b.Actually in my opinion its when konica750 comes into its own.