This mode works only in layers with Lock Transparency deselected. It’s like painting on the back side of acetate, underneath the image. This mode is available for the painting tools and the Fill command. Behind – Edits or paints only in the transparent areas of a layer.In this case, the result looks a bit like a mezzotint. Lowering the opacity (in this example the opacity of the Layer) reveals a speckled effect which is either the blend color or the base color – never a combination of the two. Dissolve – Edits or paints each pixel to make it the result color however, the result color is a random replacement of the pixels with the base color or the blend color, depending on the opacity at any pixel location.Note: the Normal Blend mode changes to the Threshold Blend Mode when working with indexed-color and/or bitmapped images. A photo will appear as the original or, if you paint with a color, the result color is the color that you chose. Results are as expected – the contents of a layer are displayed without any blending. (I point out that I’m using 100% because lowering the opacity of the layer (or paint or fill etc.) will change the way that the blend color is combined with the layer below.) When used at 100% opacity, the blend color will replace the base color. In this grouping, there is no Neutral color – all blend colors will effect the base colors. Note: the Fill command and the painting tools are the only ones that list the Behind and Clear Blend modes and are only available when working on layers that can have transparency. T he first group of Blend Modes (the ones at the top above the first dividing line) contains from one to four blend modes depending on the feature: Normal, Dissolve, Behind and Clear. In the third illustration, both layers are visible but with the Blend Mode for the leaves layer set to Normal, there is no blending between layers. In the second illustration, the photo of the leaves is visible. In the first illustration, the Background layer (the photo of the mountains) is visible. In this example there are two layers in the Photoshop document – the Background layer is a photo of a mountain and the top layer is a photo of leaves with three circles (black, white, and gray) added to demonstrate the effect of the Neutral color of the Blend Mode. For example, the Multiply blend mode has a Neutral color of white (white has no effect), the Screen blend mode has a Neutral color is black (black has no effect), and the Overlay blend mode has a Neutral color of 50% gray (gray has no effect). In addition, some of the blend modes have what are called Neutral colors, or colors that have no effect when they are blended. The result color is the color resulting from the blend.The blend color is the color being blended (the painting or editing color).The base color is the original color in the image (which can be the color on a layer or a cumulative combination of layers).When using blend modes, it’s helpful to think of the effects in terms of the following three colors: Except where noted, these modes work on a per channel basis (i.e., they treat an RGB image like three grayscale images). Within each of these different areas of Photoshop, the available blend modes vary based on which modes are useful and appropriate for each command. They can be found throughout the program in such areas as the Layers panel, Layer Styles, Painting tools, Smart Filters, the Fill, Stroke, and Fade commands, and the Apply Image and Calculations commands. A blend mode allows you to control how the pixels on one layer work with or affect (or blend with) other pixels in Photoshop.