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5. Combined use of different blurring kernels
Here I would like to suggest the joined use of a GB and SF ïŹlters (i.e. two kernels which differs in their edge-awareness) in order to modulate the sharpening. Iâm going to write some very simple and very unorthodox math; being O the Original picture, T and E respectively the Texture and Edge features of the picture (both belonging to the high frequency spatial range) weâve seen that:
GB = O - (T+E); (Eq. 5.1)
SB = O - T; (Eq. 5.2)
A subtraction gives the Edge only component:
(SB - GB) = O - T - O + T + E = E; (Eq. 5.3)
While, rearranging the second equation, we prove that Texture is boosted by SB:
(O - SB) = T; (Eq. 5.4)
This should give us all the instruments needed to modulate the sharpening in texture and edges separately, via subtraction layers/channels to be blended in LL mode. Letâs see. Following images are GB, SB versions and the scaled subtractions weâve talked about.
(Fig 5.1) Subtraction between SB (Radius=6 Threshold=15) and GB (Radius=4) to get an edge-only enhancement channel.
(Fig 5.2) Edge-enhancing channel applied to the original LL 50% opacity.
(Fig. 5.3) The result using SB (Radius = 6 and Threshold = 15) and GB (Radius = 4).
What we should see is a Edges only sharpening. So weâve been able to get a Texture and Edges sharpening (with GB), a Texture only sharpening (with SB) and an Edges only sharpening (using SB -GB). More pronounced effect can be obtained by higher opacity of the LL layers (when possible) or a sigmoid (aka S-shaped) curves adjustment layer clipped to it, whose opacity can be tweaked as well. In the ToDo list there are actions/scripts (and even a Photoshop CS4 panel) to automate the process.
A simple yet powerful Photoshop tool to effectively boost the local contrast of an image, by means of a smart algorithm which avoids the clipping issues typical of methods like shadows/highlights. The user interface is simple and clean, with just one slider, allowing the user to customize the effect in a straightforward way.
In 2000 Imacon, now Hasselblad, created a new proprietary format for the Imacon scanners, the Flexible File Format or fff. 3F has determined the biggest revolution in the field of original analog scanning since the introduction of the drum scanner.
First of all forgive us the word play, which might come off as presumptuous. However, we felt like we came up with something that perfectly summarizes our philosophy in this arena by uniting the concepts of high resolution and quality reproduction.