Suggestions for free software that can process images which have been exposed to the right?

I’d like something that’s easy to jump into even if it doesn’t give me full control. Once I’ve practiced a bit, I may use more complex software but for a first try, I’d like to keep it simple.

Huh? Images exposed to the right?

Not sure what “exposed to the right” means. A typo I suppose. But GIMP is free and does a pretty good editing job.

Maybe over-exposed? I immediately started thinking about right-leaning propaganda images so was confused.

Yes, Gimp. Also, Windows and OSX both have easy to use image manipulation tools. Nothing close to Photoshop, but they can crop, adjust color and light levels, etc.

GIMP and Paint.net seem to be the standard answers here for this question. I also recently discovered a great pack of free plug-ins for Paint.net that add a lot more photoshop-lite functionality, but are still easy to use.

Exposing to the right = leveraging the way digital cameras process data to get better signal/noise ratio: https://en.wikipedia.org/wiki/Exposing_to_the_right

The highest stop has half of the information. The 2nd highest has half the remaining info, the 3rd highest half of the remaining info. So you overexpose and then slide the histogram back to the left to uncurl the info using software. I don’t know precisely how to do it or what software would be best, though.

Troutman: Do those plug-ins (or the basic version) allow you to mess with the histogram?

Is ETTR technique only possible if you shot in RAW or can it work with JPEG too?

I can confirm that GIMP allows you to mess with the histograms as a basic function, without even getting into the plug-ins. There are, naturally, tons of plug-ins.

This article claims that JPEG dynamic range is “significantly reduced” compared to RAW, but does not give exact figures.

Only RAW. You don’t do it with JPEGs. If anything, you might expose to the left/for highlights with JPEG.

Paint.net allows some basic fiddling with the histogram, and the plug-ins allow finer control.

I have not used the free tools mentioned but I use Photoshop Elements, a “lite” version of Photoshop that costs under $100 and does a lot of what Photoshop can do. Not subscription based. Includes RAW processing. I don’t think you can directly edit the histogram but there is a histogram display in RAW processing that shows the effects of changing exposure, blacks & whites, color temp, shadows, highlights, etc.

Looking around online, it seems like GIMP along with a RAW convertor like UFRAW should work fine. I use Adobe Lightroom, but that’s not free.

LOL! You learn something new every day. :slight_smile:

And here I thought maybe it meant there was too much red in it.t I see it isn’t the Elections Forum.

You just get the photos all together and play them the first few bars of that Beyonce song over and over, until they look perfect. :slight_smile:

Once upon a time I worked with images. There was a technique called Pfizer’s adaptive histogram equalization that got spectacular results with some images(*) — results unavailable with any ordinary mapping. Does GIMP or Photoshop have plug-ins that implement that technique?

    • For example, images with both underexposed and overexposed regions (though even then an ordinary mapping might work well enough in the simplest cases).

If I understand what you mean, that’s called HDR photography: https://www.google.ca/search?q=hdr+photography&num=20&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiv9uvT67HeAhVMhOAKHb30AfUQ_AUIDigB&biw=1745&bih=862

I think years ago I found free websites that enabled that kind of processing. It must either be standard or have a plug-in for anything that’s used for general photographic processing.

The intent and results are similar. I clicked some of your links and they speak of special hardware — separate readings at the same pixel.

Pfizer’s algorithm operated on an ordinary digital image. The basic idea is very simple: Replace each luminance pixel with its “histogram-equalized” version except that the histogram to be equalized is computed separately for each pixel, e.g. by taking the histogram across, say the 99-by-99 subimage with that pixel at its center. (Never mind minor variations to reduce computation cost.)

The deal with RAW and “exposing to the right” stuff has to do with how a raw file is structured, its bit depth, and all that kind of stuff.

A RAW file is typically 12-bits per channel (4096 values) or even 14-bits per channel (16,384 values per channel.) When you display it on a monitor, or convert it to a JPEG or whatever, the information gets collapsed down to 8 bits per channel, and a gamma correction is applied to it. So there is information that is being lost in the highlight section of the histogram when conversion occurs. (And the way the luminance data is recorded, the brightest stop of a photo takes up half of the RAW file’s bits. The next darker stop is half of that, the next half of that, and so on. So there is a lot more information in the brightest parts of the photos.) So this is a technique that needs to work with the RAW file, pre-conversion to an 8-bit per channel color space. You can usually eke out about a stop to stop and a half of highlight detail that looks clipped in the in-camera JPEG conversion.