Tutorial on PIXLS.US

Highlight Bloom and Photoillustration Look

Wed, 12 Oct 2016 13:47:35 -0500

Over in the forums community member Sebastien Guyader (@sguyader) posted a neat workflow for emulating a photo-illustrative look popularized by photographers like Dave Hill where the resulting images often seem to have a sort of hyper-real feeling to them. Some of this feeling comes from a local-contrast boost and slight ‘blooming’ of the lighter tones in the image (though arguably most of the look is due to lighting and compositing of multiple elements).

HDR Photography with Free Software (LuminanceHDR)

Tue, 26 Jan 2016 14:57:59 -0500

I have a mostly love/hate relationship with HDR images (well, tonemapping HDR more than the HDR themselves). I think the problem is that it’s very easy to create really bad HDR images that the photographer thinks look really good. I know because I’ve been there:

Don't judge me, it was a weird time in my life...

The best term I’ve heard used to describe over-processed images created from an HDR is “clown vomit” (which would also be a great name for a band, by the way). They are easily spotted with some tell-tale signs such as the halos at high-contrast edges, the unrealistically hyper-saturated colors that make your eyes bleed, and a general affront to good taste. In fact, while I’m putting up embarrassing images that I’ve done in the past, here’s one that scores on all the points for a crappy image from an HDR:

Users Guide to High Bit Depth GIMP 2.9.2, Part 2

Wed, 02 Dec 2015 12:00:00 -0600

This is Part 2 of a two-part guide to high bit depth editing in GIMP 2.9.2 with Elle Stone. The first part of this article can be found here: [*Part 1*](/articles/users-guide-to-high-bit-depth-gimp-2-9-2-part-1/).

Using GIMP 2.9.2 for radiometrically correct editing

<ol>
<li><a href="#linearized-srgb-channel-values-and-radiometrically-correct-editing">Linearized sRGB channel values and radiometrically correct editing</a></li>
<li><a href="#using-the-linear-light-option-in-the-image-precision-menu">Using the “Linear light” option in the “Image/Precision” menu</a></li>
<li><a href="#a-note-on-interoperability-between-krita-and-gimp">A note on interoperability between Krita and GIMP</a></li>
</ol>

GIMP 2.9.2’s unbounded floating point ICC profile conversions (handle with care!)

Using GIMP 2.9.2’s floating point precision for unclamped editing

<ol>
<li><a href="#high-bit-depth-gimp-s-unclamped-editing-a-whole-realm-of-new-editing-possibilities">High bit depth GIMP’s unclamped editing: a whole realm of new editing possibilities</a></li>
<li><a href="#if-the-thought-of-working-with-unclamped-rgb-data-is-unappealing-use-integer-precision">If the thought of working with unclamped RGB data is unappealing, use integer precision</a></li>
</ol>

Looking to the future: GIMP 3.0 and beyond

Radiometrically correct editing

Linearized sRGB channel values and radiometrically correct editing

One goal for GIMP 2.10 is to make it easy for users to produce radiometrically correct editing results. "Radiometrically correct editing" reflects the way light and color combine out there in the real world, and so requires that the relevant editing operations be done on linearized RGB.

Users Guide to High Bit Depth GIMP 2.9.2, Part 1

Sun, 01 Nov 2015 12:00:00 -0600

Introduction: high bit depth GIMP 2.9.2

    <ol>
    <li><a href="#purpose-of-this-guide">Purpose of this guide</a></li>
    <li><a href="#useful-links-the-official-gimp-website-builds-for-windows-and-mac-building-gimp-on-linux">Useful links: the official GIMP website, builds for Windows and MAC, building GIMP on Linux</a></li>
    <li><a href="#editing-in-srgb-vs-editing-in-other-color-spaces">Editing in sRGB vs editing in other color spaces</a></li>
    <li><a href="#a-note-about-the-gamma-hack-that-s-provided-for-many-editing-operations">A note about the “Gamma hack” that’s provided for many editing operations</a></li>
    </ol></li>

<li><a href="#new-high-bit-depth-precision-options">New high bit depth precision options</a>

    <ol>
    <li><a href="#menu-for-choosing-the-image-precision">Menu for choosing the image precision</a></li>
    <li><a href="#which-precision-should-you-choose-for-editing-">Which precision should you choose for editing?</a></li>
    <li><a href="#using-the-image-precision-options-when-exporting-an-image-to-disk">Using the image precision options when exporting an image to disk</a></li>
    </ol></li>

<li><a href="#new-color-management-options">New color management options</a>

    <ol>
    <li><a href="#gimp-2-9-2-automatically-detects-camera-dcf-information">GIMP 2.9.2 automatically detects camera DCF information</a></li>
    <li><a href="#black-point-compensation">Black point compensation</a></li>
    </ol></li>

<li><a href="#new-and-updated-algorithms-for-converting-to-luminance-lab-and-lch">New and updated algorithms for converting to Luminance, LAB, and LCH</a>

    <ol>
    <li><a href="#converting-srgb-images-from-color-to-black-and-white-using-luma-and-luminance">Converting sRGB images from Color to Black and White using Luma and Luminance</a></li>
    <li><a href="#decomposing-from-srgb-to-lab">Decomposing from sRGB to LAB</a></li>
    <li><a href="#lch-the-actually-usable-replacement-for-the-entirely-inadequate-color-space-known-as-hsv-">LCH: the actually usable replacement for the entirely inadequate color space known as “HSV”</a></li>
    </ol></li>

Introduction: high bit depth GIMP 2.9.2

Purpose of this guide

As announced on the GIMP users and developers mailing lists, the recent (November 26, 2015) GIMP 2.9.2 release is the first development release in the GIMP 2.9.x series leading to GIMP 2.10. The release announcement summarizes the many code changes that were made to port the old GIMP code over to GEGL’s high bit depth processing.

Freaky Details (Calvin Hollywood)

Mon, 31 Aug 2015 14:33:50 -0500

German photographer/digital artist/photoshop trainer Calvin Hollywood has a rather unique style to his photography. It’s a sort of edgy, gritty, hyper-realistic result, almost a blend between illustration and photography.

As part of one of his courses, he talks about a technique for accentuating details in an image that he calls “Freaky Details”.

Here is Calvin describing this technique using Photoshop:

In my meandering around different retouching tutorials I came across it a while ago, and wanted to replicate the results in GIMP if possible. There were a couple of problems that I ran into for replicating the exact same workflow:

Color Curves Matching

Tue, 04 Aug 2015 14:10:36 -0500

In my previous post on Color Curves for Toning/Grading , I looked at the basics of what the Curves dialog lets you do in GIMP . I had been meaning to revisit the subject with a little more restraint (the color curve in that post was a little rough and gross, but it was for illustration so I hope it served its purpose).

This time I want to look at the use of curves a little more carefully. You’d be amazed at the subtlety that gentle curves can produce in toning your images. Even small changes in your curves can have quite the impact on your final result. For instance, have a look at the four film emulation curves created by Petteri Sulonen (if you haven’t read his page yet on creating these curves, it’s well worth your time):

Basic Color Curves

Mon, 27 Jul 2015 10:26:49 -0500

Color has this amazing ability to evoke emotional responses from us. From the warm glow of a sunny summer afternoon to a cool refreshing early evening in fall. We associate colors with certain moods, places, feelings, and memories (consciously or not).

Volumes have been written on color and I am in no ways even remotely qualified to speak on it. So I won’t.

Instead, we are going to take a look at the use of the Curves tool in GIMP . Even though GIMP is used to demonstrate these ideas, the principles are generic to just about any RGB curve adjustments.

Tutorial on PIXLS.US

Highlight Bloom and Photoillustration Look

HDR Photography with Free Software (LuminanceHDR)

Users Guide to High Bit Depth GIMP 2.9.2, Part 2

Contents

Radiometrically correct editing

Linearized sRGB channel values and radiometrically correct editing

Users Guide to High Bit Depth GIMP 2.9.2, Part 1

Contents

Introduction: high bit depth GIMP 2.9.2

Purpose of this guide

Freaky Details (Calvin Hollywood)

Color Curves Matching

Basic Color Curves