Jump to content
furtonb

Threshold adjustment cannot be flattened?

Recommended Posts

Hey guys, 

 

I'm having a problem:

 

I have an urban scale map (black and white), which I want to get rid of the smaller houses:

Before:

https://www.dropbox.com/s/ddcm2seq8pkv7ez/threshold%20before.png?dl=0

After:

https://www.dropbox.com/s/78d29hzflotnrdf/threshold%20after.png?dl=0

 

I want to export both versions of the image, but no matter what I do, merge all layers, flatten the whole document (by grouping everything and rasterizing), the ,,Before" state is exported.

 

How should I export it?

 

Thanks,

b


MBP 15" + iPad Pro 10,5"

macOS High Sierra 10.13 | iOS 11 | latest Affinity Photo & Designer & Publisher Beta

Share this post


Link to post
Share on other sites

Hi furtonb,

I'm not sure I understood your question. Do you mean that when you setup the document to show the image in the after state and flatten the document you get as a result the before state?

 

To which format are you trying to export the file? You may not even have to flatten the document depending on the file format you want to export. Simply setting the layers visibility to show what you want and exporting to JPG or PNG for example will flatten the layers for you. Any chance you can upload and link to the afphoto file you are working with?

Share this post


Link to post
Share on other sites

Wow, that was a fast response!

Yup, you got it right. Today I took a closer look again though, and the image was way too big to be noticable, but it worked - I shouldn't post when tired...

I guess the approach was not that good, but I got it solved in another way.

 

Task:

A friend of mine wanted to have this effect during his semester work, that the smaller houses will disappear over time from the map, and I suggested him to do with the Threshold adjustment (it wasn't important to take into consideration the quality/current state/etc., because it would have been too much work for a slide he is going to project). He tried it, and his problem was, that the shown appareance was different in the exported file than in the PS CC17 window, but it was due to the big file size I guess. Then I tried it myself, and got the same result in Affinity Photo as well.

 

You can test it in the afphoto I shared in the folder below (altair final map.afphoto): zooming is fit to screen, turn on the layer "applied threshold adjustment" layer in the group "threshold", that's what mislead us, we had expected to see the file as the zoomed-to-fit state shows (see the two screenshots).

It seems, that the Threshold adjustment layer is adaptive to the zoom factor, once it's rasterized, it reveals the final look no matter the zoom.

 

Solution for the task:

I think the task could be accomplished by masking the brighter spots and applying either a black inner glow to it and cleaning the edges with a Levels adjustment, or doing it with an Outline effect + Levels adjustment layer, and it is a more flexible approach to achieve what he wanted, and he is satisfied with it.

 

Files:

https://www.dropbox.com/sh/bb3psqvfu5nas2g/AAAdn9gRuGx7CfpyOJznCjL6a?dl=0

 

My question:

I would be interested in hearing your opinion about the adaptivity of the Threshold adjustment layer I was describing. Shouldn't the preview for it be precise at all zoom levels like it is for the rasterized image?

 

I hope it's clearer by now.


MBP 15" + iPad Pro 10,5"

macOS High Sierra 10.13 | iOS 11 | latest Affinity Photo & Designer & Publisher Beta

Share this post


Link to post
Share on other sites

Hi furtonb,

Affinity Photo uses mipmaps - lower resolution versions of the image - to improve its performance when rendering images on screen at different zoom levels (lower than 100%). What you are seeing is the threshold adjustment being applied to one of these lower resolution versions depending on the zoom level. Once you rasterise it, the adjustment is backed to the full resolution image instead and then displayed on screen thus the differences you are seeing between the before and after the rasterisation process. To prevent this and get an accurate "preview" of the adjustments make sure you are seeing/checking them at 100% zoom or more to ensure they are being applied/previewed using the full resolution version. 

Share this post


Link to post
Share on other sites

Thanks for the clarification, now it's clear.


MBP 15" + iPad Pro 10,5"

macOS High Sierra 10.13 | iOS 11 | latest Affinity Photo & Designer & Publisher Beta

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×