Analyser Pro, changing grades question

As we all know, Ilford filters have a consistent density from 0 to 3 1/2.

So why does the Analyser Pro change the exposure time when you tell it you are going from a grade 1 to grade 1 1/2 filter? The new exposure time is very rarely correct.

I don't have an RH Analyser Pro, but I have read its instructions. Here's a guess of the reason.
Ilford filters (under 4) have consistent density only for skin-tones. If you want some other tone to be consistent, exposure must change. The Analyser Pro might be keeping a different tone consistent for you.
Does the Analyser Pro have a way for you to tell it which tone you are interested in?
Another possible reason: RH might have wanted the tone-scale to expand/contract symmetrically when changing grade, causing them to keep middle-gray consistent and thus shift exposure.

Experiment: Enter three tones into the meter: dark, middle, and light. Then change grades and watch those three tones move on the scale. That will give you an idea of what tone it is keeping consistent.

Mark Overton

I have one but still haven't used it. However, it shouldn't be doing anything other that what you have calibrated it to do.

You arent using the lightmeter thing with filters in place?

Craig75 said:

I have one but still haven't used it. However, it shouldn't be doing anything other that what you have calibrated it to do.

You arent using the lightmeter thing with filters in place?

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Nothing to do with taking readings with the filters in place which no one does as the meter doesn't work when the filter is in place.

If I do a print at say 10 sec with the meter saying G 1 and I then change the grade on the meter to grade 1 1/2, the time changes. My question was simply, if the density of Ilford filters is the same (up to G 3 1/2) why does the exposure change? Before I got this analyser if I wanted to change filters I did, without touching exposure. This issue has nothing to do with calibration.

The Ilford filters are calibrated so zone V stays the same when you change filters and keep the exposure time the same. This makes sense when you work with proof sheets and such and feel the need to change the overal contrast of the print.

The Analyser Pro is calibrated to keep zone I or zone 1.5 constant. You measure the high lights of the negatives and these get assigned to show just a bit of texture. This of course changes the time when you change filters. Consequence is that you will see the zone V placement change, but it also will keep your highlight where they more or less should be.

markbau said:

Nothing to do with taking readings with the filters in place which no one does as the meter doesn't work when the filter is in place.

If I do a print at say 10 sec with the meter saying G 1 and I then change the grade on the meter to grade 1 1/2, the time changes. My question was simply, if the density of Ilford filters is the same (up to G 3 1/2) why does the exposure change? Before I got this analyser if I wanted to change filters I did, without touching exposure. This issue has nothing to do with calibration.

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Ahh I see. Mine is only.preset for Ilford multigrade iv so I thought you might have gone through the hell of recalibrating it for Ilford new paper.

Yes as huub says

Page 5 section 2.2 1. of the latest version of the manual explains it.

(Would have quoted it but it comes out a jumbled mess whenever I try and copy and paste)

Huub said:

The Ilford filters are calibrated so zone V stays the same when you change filters and keep the exposure time the same. This makes sense when you work with proof sheets and such and feel the need to change the overal contrast of the print.

The Analyser Pro is calibrated to keep zone I or zone 1.5 constant. You measure the high lights of the negatives and these get assigned to show just a bit of texture. This of course changes the time when you change filters. Consequence is that you will see the zone V placement change, but it also will keep your highlight where they more or less should be.

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This.

Craig75 said:

(Would have quoted it but it comes out a jumbled mess whenever I try and copy and paste)

Click to expand...

I've turned to using a screen snipping utility and pasting a jpeg instead of copying and pasting.
It is a usually a lot quicker and easier!