It's too weak. It needs to be more versatile. Maybe even allow airbrush to be enabled so the blur effect can build-up like water on a watercolor painting.
When I use your settings I get a little bit of blur. Nothing more than I normally get with blur strength at 100% without scattering, and unfortunately nowhere near enough for the color blending effect the original poster is after. Are you sure you're listing all the settings that are creating your blur tool's behavior?
Also, setting the scattering count to 16 will slow almost any CPU down to a crawl at larger brush sizes, doesn't it? When you say it works on a high res image, are we talking anywhere close to 4000x4000 and above?
Yes, that size high res. I should clarify that my solution is to increase the blur strength significantly, but not blend like watercolour as i don't think the blur tool is the right kind of tool to create his effect even if super strength was added.
Hmm, yeah, that is still too weak for color blending unfortunately. 🙂
You use a high brush spacing, which is why the high scattering count doesn't cause lag. You could also disable scattering and decrease the spacing to 2-3% to achieve a similar blur, while also avoiding the unpredictability in edge control that scattering brings with it.
Setting the size control to Pen Pressure with a minimum diameter of 100% is the same as setting it to Off by the way, so you might as well just untick Shape Dynamics. 🙂 Transfer > Strength Control set to minimum 100% also equals unticking Transfer altogether in this case.
I think the problem is that in the time since the blur tool was introduced (heck, to my knowledge it's always been there, at least since the mid-90s), resolutions for most tasks have skyrocketed. What once probably made a definite difference to our low-resolution graphics, means nothing to today's 5k+ images. And the workarounds aren't all that perfect either. The nice thing about the blur tool is that it can be gradiated, creating various degrees of blur. Where-as, copying the layer, blurring it, and masking out parts may get the right results in some cases, but it doesn't allow for subtle gradations of blur between the regions. This comes back to my bigger issue that Photoshop is really behind it "compound blurs" compared to After Effects. The only compound blur we have is the Lens Blur, the only effect not able to be dynamically inserted into a smart object, that looks to a particular channel as a blur map. Lens blurs are nice but they are often overkill and processor intensive for day-to-day needs, and their CPU intensiveness is what probably prevents them for being added as smart effects. If we could just have a regular old compound gaussian blur, that would be money.
One thing I noticed is that even if it's a very mundane change, developers are really hesitant to change the operation of existing features. This makes a certain amount of sense, as many users go "BUT WAIT, IT WORKED DIFFERENTLY THE LAST TIME I DID THIS!" Probably the best solution would be to create a toggle that says "Blur More" (which fits with their terminology), that would increase the blur by a power of x4-10 or something, and have it off by default.
I frequently need t to create layer masks around my products photographed on white - one of the most common photography scenarios. The problem is that when I convert a pen tool path into a mask, I need to be able to selectively choose which areas have a blurred edge mask, and which areas should have a sharp line in the selection. When you take pictures of small products its often nearly impossible to get everything in focus at any aperture. So this is extremely common for photographing small products. I want to use the blur tool to soften parts of the mask, but the blur tool is so weak its almost completely ineffective. I think this is because I'm always working at 5 and 6k resolutions. This also makes the blur tool useless for many photos and I have to use a blur filter instead. But a blur filter is not helpful when you are needing to selectively blur parts of the mask itself. So mask manipulation would be WAY more powerful if you would make the blur tool more powerful. Like up to 100x more powerful. I'm not sure if the blur tool is so weak because its a legacy tool from times when we only had a fraction of the resolution in our photos to work with. Whatever the reason, there are a lot of people asking for this, and it would save me hours of workarounds to have this simple obvious tool enhancement. Thank you!
Even though I don't have a need to blur that you do, I would like to see if I can help. I know a great deal about these kinds of filters so maybe I can get a definitive answer to what you want and then figure how to do it.
RONC
It's not a filter, it's a tool. The blur filters work just fine. It's the blur TOOL that we all have issues with, and there's really nothing to figure out, it just has no settings. The sad part is that other than the incredibly powerful but broken Lens Blur filter (it's the only blur that can not be used as a smart filter), the blur tool is the only way of creating a compound blur, that is, make part of an image more or less blurry than another. And as Lily Skove mentioned, that makes it incredibly useful on layer masks. I believe it's a huge oversight on Adobe's part.
BTW: I've always suspected that the "Lens Blur" filter's feature to use a channel as a blur map, is precisely the reason why it can't be used as a smart filter. That's a whole new level of computation that no other filter process has to do, and would probably be difficult to code without causing crashes. Makes me really sad, because I'd LOVE to have a compound blur as a smart filter. I often just throw up my hands and do this kind of stuff in After Effects, which has a lot better handling of compound blurs. Sorry for the off-topic.
I glean from reading this thread that Adobe does not deem this a problem. I would say that their software is doing what is mathematically correct but you don't need math here. From a quick test I made, blur works correctly for what it is designed to do. Problem is that you want what I will call un-normalized blur. Un-normalized does not divide the result by the number of filter coefficients. I'm trying to think of a way to get the same effect without changing software. I will have image showing un vs normalized in morning.
Tell me how you would do this with actual paint, canvas and brush. Do not add more paint when you blur it. The blur expands and gets weaker. Now if you un-normalize by adding paint you get what you want to do.
This is a communications problem more than anything.
I would like to see the problem that you are trying to solve with Blur. Is the anomaly separated from the background? Peter Bailey's example with the background included will always fail if you expect to cover the background with blurred data. Does someone file I can see and a few works explaining the anomaly not that Blur fails. What would you do with real painting?
I googled "why is the blur tool so weak" and got to this page so obviously I totally agree with you. Using layers and masks is sometimes more effort then I want to go to to get a blur. The effect with the tool is WAY too subtle even at 100%. I can click on an area 50 times and barely tell that anything has happened. Why not simply make 100% much stronger and let people dial it back as they wish? You could argue that you should use layers and masks for any tool - burning, curves and etc., but shouldn't that discretion be left up to the user?
I do understand that it’s not intended for effect building, but I still agree that it’s too weak. Imagine this: You are creating a mask for a person in a portrait picture. The face is usually in focus, therefore your mask don’t need a lot of feather in that area. But other parts of the person are not in focus, hence the mask needs to be blurred in those parts. But most of the times the blur can’t be uniform, due to nature of the blur in a real world photograph. Making different selections and blurring the mask with the gaussian blur filter is not really intuitive – interactively creating that blur/feather with the blur tool is way more intuitive. But with the pixel dimensions of todays photographs the tool is simply too weak for that task. In short: The blur tool is a really great mask editing tool. But in a lot of cases it's unfortunately too weak for that task.
Well, it's 2020 now and still no strong Blur tool. I understand the arguments that "It's not meant for that", "There are different ways of doing that", etc. but being able to set the strength of the Blur tool to "stronger" than the very mild blurring it does at 100% still doesn't seem like asking for an awful lot.
For an example of how easy it really is, download and install Paint.NET, install the TR's Dodge and Burn (and blur) plugin and there you have it. A blur tool that when set to 80-90% will REALLY blur with a brush. "Why not use it then, and leave Photoshop alone," you ask? Because my workflow is in Photoshop, not in Paint.NET, that's why.
Krita's brushes can have filters from Krita applied to them. They can use the filters as brushes.
There is a brush preset called Filter_Blur that blurs the pixels as a brush.
Its default blur value it's too weak for very big images with a high pixel density, but you can easily edit/customize the brush. You click on the brush icon at the top of the program, bellow the Settings, Window, Help buttons and select the Filter tab, then change the Horizontal and Vertical Radius (radii/radiuses) to make the blur stronger.
You can save this custom brush preset. Then you can use the Opacity slider to have a stronger or weaker effect while painting.
This blur tool can be a little slow on 2014 cpu (without AVX2) if your stroke is long and you are using a bigger image, e.g. 1474px X 2208 px at 300 ppi. The cpu is not maxed out when using the brush.
The performance is decent for a strong blur effect and moderate brush stroke speed. The advantage over other programs is that you don't have to use a new layer for the image that is blurred at a constant blur value, therefore you don't have to duplicate the image, blur it and mask the regions where you don't want the blur to show up on the original image below.
So Krita allows for a lot of different blur values inside a single brush without using layers.
Krita's blur tool workflow was better than the that of the "TR's Dodge and Burn (Blur and Sharpen)" Plugin for Paint.Net which is slower and not as .
On an lage image: 7360 px X 4912 px at 300 ppi with a high blur value, the brush is very slow, with a 780px brush. With a 180 px brush size, the brush is slow. If you move the brush slowly the effect is live.
Clip Studio Paint has a stronger and fastert blur tool than Ps, Painter or Krita. On an lage image: 7360 px X 4912 px at 300 ppi with a high blur value, Krita's blur brush is slow while the blur brush in Clip Studio Paint is usable. The blur brush in Clip Studio also gets slow with huge values, but is the fastest in this software compared with the rest of them.