site updated 2008/01/08
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zipped last on 2008/01/08
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Introduction

abstract . overview
new . since last release
install . getting started
colorspaces . linear
gamut . and color
list . of all actions and scripts
migration . from FFDD5

Examples

contest . user photos
development . details
stitching . workflow
darken . LDR development

Pre-Processing

shooting . bracketing technique
batch . blending

Development

knee . highlight control
dodge . custom exposure
gnd . graduated exposure
contrast . adjustments
zone . check development
gray . b&w conversion

Post-Processing

denoise . noise reduction
sharp . bring in focus
double . image size
grain . add film like grain
gloss-diff . removal

Miscellaneous

blog . notes and future
performance . photoshop tips
cache . photoshop cache levels
license . agreement

Post-Processing / Gloss-Diff

Actions

1. gloss-diff/new * [m] : Batch friendly way to reduce gloss differential problem.
2. gloss-diff/custom [m] : Custom level of gloss differential reduction.
3. gloss-diff/* [l] : Change current gloss-diff layer to a different setting.

These actions are designed as a workaround for the problem of gloss differential between the whites (areas that would receive little or no ink) and the rest of a glossy or semi-gloss print. The gloss-diff/custom [m] action provides a user adjustable way to reduce the output level of the whites only so that white areas in the output print receive enough ink to have the same gloss as the rest of the print. This action does not effect saturated colors, so all non-white areas will be as vibrant as possible.

The gloss-diff/custom [m] action will produce a Levels dialog that can be used to fine tune the effect. The Output White Point (which defaults to 245, see image below) can be used to adjust how much to reduce the brightness of the whites. A setting of 245 works well for Epson K3 inks on Epson Premium Luster Photo Paper when the colorspace is ProPhotoRGB. Other paper and ink combinations will require different settings.

With the gloss-diff layer selected, the gloss-diff/* [l] actions can be used to make an adjustment to the levels setting after the gloss-diff/custom [m] action has finished. The * ranges from 231 to 249. This action can also be used for batch processing. The gloss-diff/new * [m] actions create a gloss-diff layer where * represents the level setting ranging from 231 to 249.

The goal is to reduce the brightness by the smallest amount possible that corrects the gloss differential problem. The best way to determine this is to print a photo overlayed with large squares colored to the top 55 gray tones starting with white [255,255,255] and ending with [200,200,200]. Then find the brightest square which does not have a gloss differential. If the square represents gray shade [249,249,249], then value 249 would be used in the Levels dialog.

Colorspace Conversions

The image's colorspace will effect the setting that should be used for the gloss-diff action. Below is a quick lookup table that can be used to convert settings between types of colorspaces.