Adobe Photoshop CS4 - Manual (Page 321)

314 USING PHOTOSHOP CS4
Layers
Last updated 1/10/2010
2 Make the desired changes in the Adjustments panel.
Note: Inverted adjustment layers do not have editable settings.
Merging adjustment or fill layers
You can merge an adjustment or fill layer several ways: with the layer below it, with the layers in its own grouped layer,
with other selected layers, and with all other visible layers. You cannot, however, use an adjustment or fill layer as the
target layer for a merge. When you merge an adjustment or fill layer with the layer below it, the adjustments are
rasterized and become permanently applied within the merged layer. You can also rasterize a fill layer without merging
it. (See “
Rasterize layers ” on page 295.)
Adjustment and fill layers whose masks contain only white values do not add significantly to the file size, so it is not
necessary to merge these adjustment layers to conserve file space.
Nondestructive editing
About nondestructive editing
Nondestructive editing allows you to make changes to an image without overwriting the original image data, which
remains available in case you want to revert to it. Because nondestructive editing doesn’t remove data from an image,
the image quality doesn’t degrade when you make edits. You can perform nondestructive editing in Photoshop in
several ways:
Working with adjustment layers Adjustment layers apply color and tonal adjustments to an image without
permanently changing pixel values.
Transforming with Smart Objects Smart Objects enable nondestructive scaling, rotating, and warping.
Filtering with Smart Filters Filters applied to Smart Objects become Smart Filters and allow for nondestructive filter
effects.
Adjusting variations, shadows, and highlights with Smart Objects Shadow/Highlight and Variations commands can
be applied to a Smart Object as Smart Filters.
Retouching on a separate layer Clone Stamp, Healing Brush, and Spot Healing Brush tools let you retouch non-
destructively on a separate layer. Be sure to select Sample All Layers from the options bar (select Ignore Adjustment
Layers to ensure that adjustment layers won’t affect the separate layer twice). You can discard unsatisfactory
retouching, if necessary.
Editing in Camera Raw Adjustments to batches of raw, JPEG, or TIFF images preserve the original image data. Camera
Raw stores adjustment settings on a per-image basis separately from the original image files.
Opening Camera Raw files as Smart Objects Before you can edit Camera Raw files in Photoshop, you must configure
settings for them with Camera Raw. Once you edit a Camera Raw file in Photoshop, you can’t reconfigure Camera Raw
settings without losing the changes. Opening Camera Raw files in Photoshop as Smart Objects enables you to
reconfigure Camera Raw settings at any time, even after you edit the file.
Cropping non-destructively After you create a cropping rectangle with the Crop tool, select Hide from the options bar
to preserve the cropped area in a layer. Restore the cropped area anytime by choosing Image > Reveal All or by
dragging the Crop tool beyond the edge of the image. The Hide option is unavailable for images that contain only a
background layer.
Masking Layer and vector masks are nondestructive because you can re-edit the masks without losing the pixels they
hide. Filter masks let you mask out the effects of Smart Filters on Smart Object layers.