Questions and Answers
The Demo version of Neat Image has some of the functionality disabled. For example, Neat Image standalone does not save images in TIFF format and does not copy output image to the clipboard (the Demo edition only saves images in JPEG with fixed quality). The Demo plug-in for Photoshop processes a part of the input image, if the image is larger than 1600x1600 pixels. Non-Demo versions do not have those limitations. Please see Feature map for more details.
That is not necessary. The Home / Pro edition can be installed over the Demo edition.
That is not necessary. A newer version can be installed directly. It will either replace the old version (if it is an update of the old version) or will be installed and work alongside the old version (if it is a new major version).
The crystal-like artifacts (usually these are the residual compression artifacts or residual noise) look like thin lines in the filtered image. They can be eliminated by increasing the high frequency noise level in the filter settings or by using the dedicated Artifact Removal filter available in Neat Image.
Note: presence of many residual artifacts may be caused by using a poorly built, inaccurate noise profile or a profile built for another device and/or device mode. Therefore the solution could be re-building the noise profile.
The reason is that too much filtration has been applied. Let Neat Image keep some noise to produce more natural-looking results. Adjust the noise reduction amounts; for example, set the Noise Reduction Amount: Luminance control to 30-50%.
Also, make sure the device noise profile does match the input image processed. Using an incorrectly chosen or poorly built noise profile can either produce plastic-looking results or leave residual artifacts (see the previous question).
The term (spatial) frequency is used in Neat Image to denote elements of an image (both important details and noise/grain) of certain size.
High frequency corresponds to elements of smallest size.
For reference, see the noise samples of different frequencies in the Noise Filter Settings tab of the Neat Image window.
Set the value of the luminance (Y) channel noise reduction amount (in the Filter Settings box) to 0%. That will disable filtration in the luminance channel and Neat Image will only filter the color noise.
YCrCb is the name of a family of color spaces widely used in digital imaging, television, image compression (e.g., the JPEG compression stores color images in this space), etc.
In 'YCrCb', 'Y' corresponds to the luminance channel, 'Cr' - to the Cr chrominance channel covering the red to blue-green range, 'Cb' - to the Cb chrominance channel covering the blue to yellow range. Because this space enables easy separation of the luminance and chrominance information, it is very suitable to conduct noise reduction.
Such operations as tonal/color correction are quite conservative from the standpoint of noise, i.e., they do not significantly change the noise characteristics of the image. Therefore, filtering before or after is about the same as long as the noise profile is built and applied at the same stage of image processing. For example, do not use a device noise profile built with an unprocessed (with the color correction not yet applied) image to filter a processed image.
Some digital cameras apply some color correction internally. Other cameras allow access to unprocessed RAW data. Neat Image is a generic filter, which can be applied in both cases. The only requirement is to build and use a noise profile in the same point of the post-processing workflow.
On the other hand, image sharpening applied to a noisy image makes it much noisier. It is best to apply Neat Image filtration before sharpening. However, the sharpening and noise filters of Neat Image itself can be used together because Neat Image's sharpening is applied AFTER its noise filtration.
If you are not sure, try to use Neat Image as close to the source of the input image as possible.