Ralph Book / Printing. Expose for highlights, control the shadows with contrast

[lhalcong]

In Ralph Lambrecht's book, as well as many other documents, it is stated that during high quality prints , we must expose for the highlights and then find the optimal shadow density by controlling paper contrast. However, in my experience I have found I believe with certainty that once I have a base exposure that is good for highlights , changing the paper contrast will not only make the shadows darker but also makes the highlights brighter. (affecting contrast in both directions, not just the shadows). So my previous time exposure that was optimal for the highlights is no longer good and I must modify it. What am I missing ? or where did I misinterpret Ralph's book ?

Thank you for any clarifications.

 

[RobC]

I don't have his book but you should check to see if he is recommending using Ilford contrast filters. Are you using them?

Different filters will give a diffeerent speed point where the contrast curves cross. Ilford filters on the old MGIV crossed on a highlight density so that changing contrast would change the highlights little whereas there would be a much greater change in the shadows.

However, dichroic colour heads may produce a speed point somewhere in the mid tones in which case a change in contrast will change both ends of the contrast curve unless you have calibrated your Y+M filter settings to set the speed point on a highlight value.

This is further complicated by the fact that different papers will behave differently and some dichroic heads and the recommended Y+M settings for them are less than accurate.

And I'v been told that the new MGIV Classic paper behaves differently than the previous MGIV paper.

These things are never exact and there is always some tweaking of print time required when you change contrast.

So it comes down to the type of filtration you are using, the paper and its age, the developer, and if you're using colour head filtration, its calibration.

I guess that isn't really what you wanted to hear.

 

[MattKing]

Way Beyond Monochrome includes instructions on how to re-calibrate your approach to ensure that the dichroic filter settings on your colour head are speed matched on the highlight exposures.

The Ilford and Kodak filters are speed matched on a mid-tone - if you change filters the highlights will change.

 

[RobC]

the ilford filters are speed matched on a print density of 0.3 which is a highlight tone. 0.7 is a midtone.

At least thats how it used to be but apprently the new MGIV Classic paper responds differently and the speed point may be on pure white.

As I said, it depends on various factors which you will need to determine so that you know how to proceed.

 

[gzinsel]

I am a betting man, and i am going to assume you are using 6x6 filters in a condenser head,. . . correct? if so, your filters will cause different times, due to different densities, regardless of contrast.

 

[Doremus Scudder]

Long story short: whenever you change print contrast, you need to make a new test strip to re-find your optimum exposure for the highlights. This can be alleviated somewhat if you calibrate a color head to give the same exposure at a highlight density that you use most often for determining correct highlight exposure, as outlined in "Way Beyond Monochrome." Nevertheless, this only gets you in the ballpark. Fine adjustments will always still need to be made.

When I make a test print and find I need to alter contrast by about a full grade, I'll simply dial in that contrast and start over from the very beginning. For small "tweaks," I'll change contrast filtration and maybe guess at an adjusted exposure, make a print and then make exposure adjustments based on that.

What I think you're "misinterpreting" is the amount of attention to detail and the number of test prints you need to make to arrive at a fine print.

Best,

Doremus

 

[JackRosa]

Zone Master II

Or you could buy a Zone Master II and never have to worry . . . .

 

[RobC]

Or you could buy a Zone Master II and never have to worry . . . .

Heiland Spligrade printing module...