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What are the real LAD values for Kodak 2242?


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#1 Evangelos Achillopoulos

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Posted 26 June 2007 - 10:17 AM

When I measure the base of 5242 inter negative I get R0,14 G0,55 B0,93 status M densities. 5242 is with acetate base.

Kodak says that the Gray card for 5242 & 2242 should be R1,10 G1,45 B1,55 which is true for 5242 but not for 2242.

If I measure the base of 2242 inter negative I get R0,08 G0,60 B0,66, the difference is the base material which is, in case of 2242, estar.

So between the two types there is a huge difference in base density of R+0,06 G-0,15 B+0,27. In blue the difference is huge.

How came, and in the Kodak technical papers are having the same LAD values?

I haven?t been able to get this numbers from 2242.

I compare the measurments of LAD from both 5242 & 2242 and I found that If I subtract the base densities from both measurements, I?m getting exactly the same values of 0,7 in all colors (RGB).

I?m having a feeling that 2242 needs a special pre filter to be added in the positive printer (to print in 2383) in order to fix the blue, in contrast of 5242 that doesn't need it. I also think that there is an error in Kodak documentation that says, both films are having the same LAD values in status M.

Any suggestions? John, Dominic ???

Edited by Evangelos Achillopoulos, 26 June 2007 - 10:19 AM.

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#2 John Pytlak RIP

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Posted 26 June 2007 - 02:33 PM

The LAD aim for triacetate 5242 and polyester 2242 are the same. I question the large difference you found between the D-mins of the two products. Perhaps one of the films changed with aging?
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#3 Dominic Case

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Posted 26 June 2007 - 07:10 PM

You may have a very old batch of 5242. Earlier versions of this stock did have a higher blue D-min: or maybe your batch has increased its blue D-min with ageing, which tends to affect the blue density the most.

As John says, batches of both 2242 and 5242 should have very similar D-mins and should show very similar LAD values - and therefore should be printed at very similar lights. But don't expect a dupe on '42 to print at the same light as an original camera negative: that has never been the case. You don't need a filter in the printer - that is what the printer light range is there for!

By the way, the pink colour of intermediate stocks, like the orange/pink of camera negative, is not base density. All these stocks are on a clear base. It is the colour of the integral colour masking dyes in the developed emulsion layers themselves.
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#4 Evangelos Achillopoulos

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Posted 27 June 2007 - 05:05 AM

The stocks are quite new, something is wrong here, am in the investigation process?

In order to assist me:

If I subtract the base density from the gray patch, is it correct to find 0,7D status M in all RGB?

Thanks in advance
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#5 Dominic Case

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Posted 27 June 2007 - 07:34 PM

Have you taken this to your Kodak representative?

If you have found a major difference between the documented D-min and the actual D-min, that would be something that the supplier ought to be helping you with!
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#6 Evangelos Achillopoulos

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Posted 28 June 2007 - 02:07 PM

Dominic, John, everyone?

False alarm the lab guys, didn?t ever had print with that film, they didn?t new that they have to add some pre filters and they were telling me that the LAD that I print with my CRT printer was wrong...

They found out what they have to do with the contact film printer and everything now its fine...

Dominic,

Since 2383 cant go higher than 3,7D which is no more than 1,25D on the negative why we have to print (CRT negative print) in densities like 1,7D or 2,0D?

Except in the case of creating heavy negative in order to have more dense blacks but this again doesn?t need more than 1,4D to be achieved?

Thanks
For the help and sorry for the buzz?

Edited by Evangelos Achillopoulos, 28 June 2007 - 02:09 PM.

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#7 Dominic Case

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Posted 29 June 2007 - 02:45 AM

For accurate reproduction, it is important that you expose onto the linear portion of the negative's characteristic curve.

That means avoiding the toe end of the curve, which only straightens out about 0.30 above Dmin. Negative densities below that are not much use, they would lead to milky shadows (like underexposed camera negative) if you exposed onto that density range.
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