Overview

As you can see there are three types of layers:

• source image layer
• conversion layer
• action layer

Source Image

Currently there may be only one source image layer and it's always first layer on the stack. This is the place where original image is stored.

Conversion

Conversion Layer is used to change the colorspace.

You always start in RGB. If you want to edit your image in LAB colorspace, you need to create LAB conversion layer.

It is possible to change colorspaces many times on layer stack, thanks to the quality of math operations in delaboratory you don't need to worry about conversion errors.

Curves

Curves are probably most important tool in the retouching process. If you don't know how to use curves, you need to learn it or you will miss a lot.

Curves in delaboratory work same way as in other applications. You set the control points and destination channel is calculated by processing source channel with bezier curve.

Curves are easy to start with, but very difficult to master.

Mixer

Mixer is used where curves are unusable. It's more difficult tool, requires more experience.

Mixer in delaboratory also works same way as in other applications. You set the sliders and destination channel is calculated by processing ALL source channels with weights you set on sliders.

Mixer is also used in the BW conversion layer.

Apply Image

Apply Image is used to use another layer or single channel from another layer.

By default it uses layer 0 (source image) so when you create "apply image layer" you will see just copy of original image. If you decrease opacity you will bring back your modified image - so you can use to mix your effect with the original image.

If you apply the same image you are editing (you set the last layer in apply image dialog) you will achieve the same effect as "duplicate layer" in Gimp or Photoshop. This technique is used for instance to blend image in overlay/multiply/screen modes.

You can also select "single channel" and - for instance - blend your image with "green channel", this technique is sometimes used for portraits (in this case use "apply luminance" mode).

Blur

Blur is used to make image unsharp.

It is used mostly in cooperation with blend in advanced effects, like shadows & highlights or to give image dreamy look.

Making whole image unsharp without any blending/masking is not a good idea.

USM

USM means Unsharp Mask and it's sharpening tool known from other applications. There are three sliders: radius, amount and threshold. There are 4 presets to help you. HIRALOAM means "high radius low amount" and it's well known technique (popularized by Dan Margulis) used to increase local contrast.

WARNING sharpening is different kind of algorithm - it's not really scalable as well as other layers. Delaboratory always display scaled down image - you can't zoom, yet. It means that what you see on screen may be different than final result. Watch exported image to make sure your settings are correct. You have been warned.