DigitalNeg linearization not creates a white with a tone

My digital neg linearizations do not create sufficient density to make the white as bright as the paper when I make PtPd prints. Some tone remains on the print where it should be paperwhite, even in the borders outside the image. The curve that I am using is very well linearized. the darkroom is standardized and calibrated. The printer heads are working well.
How can I make the paper white as a target density for the white point on the print?

IMG_3609 Graph

please upload a .zip of your curve, thanks!

-Walker (3.4 KB)

Hi Walker, I uploaded the curve just now in a separate post.

Looking at the #k values, they are much much lower than your original Print Out Master curve. But they are also much lower than my curves were only a month or so ago.

This makes sense to me because your original master created a chart with a lot of the higher values blown out, and my recent charts also needed some highlight reductions.

However, all my charts over the last 6 months have had Density values 0.03 to 1.35, This has been consistent, so I know my brightest point is not really changing no matter what curve I use.

Could it be some fogging in the chemistry? That doesn’t feel right - the darkroom has no UV light in it.

Could I try Ink Limiting at the 255 level? Perhaps I raise the 255 level to 125%? This adds #k to the first lines of a new curve.
But I am feeling my way here. Will making this change make it hard to get linearized values in the highlights below the the 255 level?

You have been not correcting for reversed (aka fogged) highlights. Or something like that is going on creating a highlight input limit every time you linearize something like this:

Screen Shot 2021-01-26 at 8.13.04 AM

I went ahead and copy/pasted the first line of each channel of the master curve into the first line of each channel of your curve. Then I smoothed at 100% a few times (copy/pasting the smoothed values back into starting curve etc).

The final curve looks like this and should print correctly:

Here you go: (3.5 KB)


Hi Walker, that’s great, thank you. I will print and get back to you later today with the result.

How can I prevent this problem re-occurring? I must have made 75 or more linearizations, each one moving further from the master curve as I worked through different problems, chemistry, paper and darkroom conditions. If my linearization is always limiting slight the white point because of slight fogging, then should I compensate for this? How would I do that? Put my own highlight reading into the measurements column, slightly brighter than the actual measurement? Or attempt what you did each time and put in line 1 of each channel from your master? Is there any way to prevent it happening and keep the highlight at white?

As long as you correct the falses in the highlights it will work.


Thanks Walker,

I’m using 31 step x9 averages so I never get false readings. Maybe the white drifted for some other reason? I’ll keep an eye on the first line numbers, and the shape of the ink channels.
The new curve works great btw.