auto levels - threshold / settings?

[jorismak]

Hi there,

 

PS has the options in the levels dialog to do an 'auto levels', but more importantly to set the thresholds for it. You can enter an amount of percentage of signal at which you want the set the level-markers so to speak. And then it has options to do that for every channel separately, or to keep the overal link between channels and a few other options.

 

Is there something like that somewhere in Photo?

 

The per-channel thing I can do by separating the channels into a R, G and B layer and doing 'auto levels' on those layers... but I want to set the thresholds somewhere :).

 

 

[Fixx]

AutoLevels and AutoCurves are in the wish list. I have not much use for threshold (even if it is nice) as I always handtune anyway.

[jorismak]

There _is_ an Auto Levels.. and an Auto Contrast, Auto Color, Auto Whitebalance (which is really funky :P).

 

I'm specially asking for the thresholds.

 

Doing it manually is of course what I'm doing now, but the levels dialog is so f*cking small you cant' really see what you're doing in the regions where you have less than a few percent of signal.

 

A log-view or something else to make the difference more extreme can also help.

[Fixx]

No, the AutoTools that are available a dumb tools, you cannot adjust them. Curves and Levels should have autofunction that you can adjust, and indeed the tool is so f*cking small you cannot adjust it reliably. Just finding white and black points in curves is not so easily done.

[hlarledge]

There _is_ an Auto Levels.. and an Auto Contrast, Auto Color, Auto Whitebalance (which is really funky :P).

 

I've noticed when I open images in Photoshop that I've Auto-leveled and exported from Affinity Photo, I can click Photoshop's Auto-level option and get a vastly different looking image.

How do we know which "auto-level" is more accurate?

[specworkfan]

On 2/27/2017 at 3:22 PM, hlarledge said:

 

I've noticed when I open images in Photoshop that I've Auto-leveled and exported from Affinity Photo, I can click Photoshop's Auto-level option and get a vastly different looking image.

How do we know which "auto-level" is more accurate?

 

By the dyanmic range present. You can use the color picker to see the values. It will work the same in 16, 24, or 32 bit. Auto-level is normalizing the values of the image. Think of warping a sound in Ableton to fit the beat, or time stretching a clip in Final Cut Pro. These are using similar alogrithms.

I was dissappointed today to find out Affinity doesn’t have a good way of adjusting levels mathematically like Photoshop. I paint depth maps, but it’s very difficult, if not impossible, to paint a depth map with the full dynamic range. You simply need colors relative to each other, and that is feel. For certain uses though, these relative values might only be 1/3 of the dynamic range possible, so being able to drag the levels around or hit auto for max range is very useful.