LAD test film- a little clarification please.
Posted 29 August 2008 - 12:57 AM
Posted 29 August 2008 - 02:48 AM
A LAD film is a piece of correctly exposed and processed negative that is used by a laboratory to set-up their analysers and to ensure that the duplication and printing processes are correct. There are three grey patches to represent white , black and grey. The stock manufacturers publish Red, Green and Blue densities to aim for when printing.
Could I get a brief over view of Laboratory Aim Density test film? How exactly does it work. Is is processed along with exposed film to test the consistency of the processing machine and exposure or is it per-processed to use as a standard for densitometers so processed film can be compared to the test strip? I THINK I remember reading about this in Dominic's book Motion Picture Processing, but I'm drawing a blank right now.
For example the figures for Agfa CP30 for the grey patch are 1.15 Red, 1.05 Green and 1.05 Blue.
Kodak publish figures for LAD densities for interpositive and duplicate negative. The laboratory will adjust their printer settings so that when the LAD negative is printed it will produce an Interpositive with the correct densities and when that is printed, the duplicate negative will have the correct densities. LAD makes sure that you will get the best possible result from duplicating.
It is also a great aid to setting your printer to get the right colour balance on your print stock. You make a print using the LAD negative, measure the grey patch and calculate the difference from the LAD densities and this will tell you how much to alter the trims to get the print correct. Every printer point will change the print density by 0.07. So if the Red density was 1.22 then you would have to reduce the Red light by 1 point.
If my memory serves me correctly the LAD was invented by John Pytak.
Posted 29 August 2008 - 02:54 AM
Posted 01 September 2008 - 01:49 AM
Posted 01 September 2008 - 05:44 AM
Posted 03 September 2008 - 03:55 AM
I didn't realise that you were limited on the total of attachments. Here is the China Girl.
Oh woops - I lost the China Girl!
Posted 03 September 2008 - 04:34 AM
Posted 03 September 2008 - 09:06 AM
Yeah, I had that problem too, what you have to do is upload the photos on the hosting site like PhotoBucket.com then click on the IMG and it will automatically copy it the img for you then just paste it in you post and you can put up as much image content as you need. And hey no need to apalogize for the China Girl, she looks great for a lady of her age I would love the see the B&W lady as well. This is very interesting stuff!
I have put the three images on a file sharing site. I have also included a positive image of the B/W lady that has been duped so many times over the years it is no longer recognisable. I make a point of photographing or scanning anything unusual in the film world as I move about. I have quite a big selection of odd colour processes, perfs and so on.
these are the URLS:
Posted 03 September 2008 - 11:31 PM
Posted 03 September 2008 - 11:37 PM
I make a point of photographing or scanning anything unusual in the film world as I move about. I have quite a big selection of odd colour processes, perfs and so on.
Do tell, hummmmm, any chance of sharing....maybe. (Oh and if you get the IMG code on the pics and copy and paste in the body of you posts, the pics will appear in your post without effecting the amount of space you have. Just FYI in case you were unaware of that.)