Optimalist

Hi Everyone (@Old Bruce@PixelPest@lacerto@thomaso@JimmyJack@David in Яuislip@John Rostron), Sorry for my absence. Apparently, on my first day on this forum, I went over my allowed number of posts and couldn't reply to anyone anymore. After downloading a trial version of Affinity Photo, I was able to confirm @thomaso's assertion that applying any kind of gradient to a Gaussian filter does not affect its blur radius (or sigma), but instead merely its opacity. The depth of field effect does change blur radius—but it doesn't use a Gaussian blur. It may be a bokeh blur or something else. In any case, I can't use that kind of blur because it doesn't have the right properties and causes strange overlapping effects. See the image (and .afphoto file) below. On the left half of the image is a depth of field effect, with everything out of focus except for the center of the left spiral. Note the darkened areas where the blurs overlap and produce pattern artifacts. On the right half of the image is a Gaussian effect. Note that it does not produce any pattern artifacts—just blur. How they blur differently is most obvious where they're side-by-side, at the center spiral. This brings me to conclude that none of the tools in the Affinity suite of products produces a Gaussian blur that gradually increases from no blur to a certain level of blur. (I have no idea if any other image editing products do, either.) So it seems that I'll have to resort to the "brute force" method that I described in my original post. It will be a pain to implement, but at least it will look very close to perfect. Thanks for the ideas, suggestions, and thoughts! DOF v Gaussian.afphoto

Thanks for scrutinizing that, @thomaso! In the video clip, the demonstrator even calls it a "depth of field effect," which it apparently is not. I'll look into the Depth of Field Filter after I download Affinity Photo and get oriented. But now I'm wondering whether the Depth of Field Filter uses an actual Gaussian blur or some other variant. It may sound "nitpicky," but I'm not using this for just an aesthetic effect (i.e., to make a pretty picture). In any case, I'll do some exploring of Photo's capabilities as soon as I get a chance. Tschüß from a suburb of Stuttgart.

Happy flying, @David in Яuislip.

@David in Яuislip, I'm almost certain now that it can't be done in Designer (or Publisher). But apparently it can easily be done in Photo (see https://player.vimeo.com/video/296616219?h=3ee0503877&title=0&transparent=0&app_id=122963, from 1' 35" onward). Although in the example, the demonstrator is using a linear gradient on Live Gaussian Blur (see 2' 30", where he changes its extent), the actual blur is changed from one part of the image to the other. That is, it's not a mere opacity transition. In any case, thanks for your efforts. Learning other approaches and what can't be done is also helpful.

@David in Яuislip, This is how your BlurDecayed.apub image turned out when I only switched the images, but left everything else the same. Notice that the blur doesn't actually change; it merely fades in with increasing radius. In the garden scene, it's hard to tell what's actually happening in the transition area. BlurDecayed.afpub

@David in Яuislip, Looks like Publisher can do the same thing as Designer, in this case. Unfortunately, it's not an actual gradual change in blur these apps create, but a gradual change, via transparency, from one specific blur to another (or no blur). With complex, natural scenes, this isn't all that noticeable. But for other kinds of images (e.g., MRI scans), it can be. Well-illustrated example, BTW.

@Old Bruce, But it seems I need to use a "graduated mask," which Designer apparently doesn't have. Since I only need it for literally five images, I may just download the trial version of Photo, where I can at least do the work precisely. Thanks, again.

Hi @Old Bruce, Nice image! You did find a solution, but only to the part of my original post that you quoted. The very next sentence is Unfortunately, your image has a "sharp" change from the non-blurred to the blurred area. It has to be gradual (and the transition zone has to be precisely defined). In any case, thanks for the input.

After posting my question, I stumbled across Affinity's "Gradient tool" video, at https://player.vimeo.com/video/296616219?h=3ee0503877&title=0&transparent=0&app_id=122963. Beginning at 1' 35" into the movie, the topic of "graduated masks" is introduced. There, the Affinity guy explains how to achieve a closely related effect in Affinity Photo by applying a gradient to a "Live Gaussian Blur" (whatever that is). Since I don't have Affinity Photo and normally wouldn't need it, I'm wondering if there is anything in Designer that can effectively do the same thing. I don't use image editing tools every day, so I don't yet know all that Designer can do—and can't. If you know both Photo and Designer, maybe you could tell me what options are available to me. Thanks!

Hi @John Rostron, Thanks for the quick response. The approach you're suggesting seems to be basically the same as the one I mentioned was suggested in a prior post. Unless I missed something, that doesn't actually produce intermediate levels of blur, but rather various blends of blur and non-blur. That wouldn't work for me. Thanks, though.

For Affinity Designer . . . I'd love to provide an image of what I'm trying to achieve, but I'm still working on it and am hoping there's a more elegant way. One might describe my current approach (mentioned at the end) as a "brute force" method. Hopefully the following description will be enough for you to visualize it: Imagine an image to which a Gaussian blur has been applied. Now imagine a circular area within this image where this effect is not applied. This "no-effect" area should not be sharply delineated from its surrounding area; rather, there should be a transition zone within which the degree of blur gradually increases from an inner radius to an outer radius. Within the inner radius there is no blur; outside of the outer radius there is the image's overall blur; but in the transition zone between the inner and outer radii, the blur gradually increases from no blur to the overall blur. Someone on this forum previously asked about creating a blur gradient, but the solutions suggested seemed to amount to overlaying non-blurred and blurred variants of the image and then faking the transition from one to the other via a graded transparency. But that doesn't really transition the degree of blur, and for me it would be too crude of an approximation. So unless or until someone can save me from self-torture, I've decided to do this: Overlay several identical images. The bottom one is blurred at the overall level. The top one is not blurred, but is made transparent outside of the inner radius. Between the top and bottom, going downward, is a series of increasingly blurred images, each with a slightly larger opaque radius than the one above it. The last of these has the outer radius size and is only slightly less blurry than the overall level of the bottom image below it. So basically it's a stack of increasingly blurred images with increasingly large visible areas. For a more gradual effect, I can create a larger stack with smaller blur differences between images (up to Designer's limit). Is there a better way?!