"Ghost" edge lines appearing when masked image placed into another image

[TexanInParis]

I'm creating a file that's a series of overlaid images showing the construction of a building model.  I started a new document using the FHD 1080p (1920 x 1080) template and then flood filled it with  a background color compatible with my construction images.

To create a new layer, I do these steps.

1) Starting with a blank workspace, I drag and drop a jpeg file containing the image for the next layer of construction. Images were shot on a wood veneer table, so I do the following steps to isolate the image to Place into my master document.

2) Crop and rotate the imported image, leaving the aligned bottom edge of the construction image against the bottom of the edited image and the lower corners of the image (all are basically a quadrilateral with a wider bottom than top) at the lower left and right of cropped result.

3) Choose the Selection Brush and delineate the area I want to keep.

4) Use Refine to make sure I have all the elements of the layer and none of the wooden table.

5) Select New Layer with Mask and hit Apply.  When I first saw this "ghosting" I thought leaving the original layer behind the cropped layer and its mask might be the cause, so I was deleting the original layer and leaving just the cropped selection and its mask. Turns out it makes no difference.

6) Save As the cropped and masked image as .afphoto

7) Open the master document that start out as a plain image all one color.

8). Use File / Place and select the .afphoto saved in Step 6.  Size and place the image towards the bottom of the master document and centered. (I'm using X: 330 px; Y: 820 px; and Width: 1260 px.)

9) Starting with the second image, the perspectives don't exactly match the base layer because I wasn't precise about the height and angle I used to shoot each individual photo. To fix this, I use the Perspective tool to correct the sides and top edge to exactly match the layer below. When I get it corrected, I save the master file with the new image layer.

10) To get my set of final images, I make each layer visible one at a time. I then Export the document with the single image layer revealed as a .png file.

I can see on the screen before I do the export that there are "ghost" edges appearing.  These edge lines also appear in the exported .png file.  (See attachments.). Because this image starts with a single flat color, I can "fix" it before each export by painting over the lines with the same color using the Paint Brush tool.  Crude, but it seems to work.  I can't imagine what I'd do if the area behind the cropped and placed images was another complex image.

The first attached image shows the center of my workspace in my master document with the base layer placed - no funny edges. The second image shows what it looks like after I place a second layer and align it using the Perspective tool (which I'm aware changes the .afphoto file into a pixel layer).  The image is selected, and you can see the boundary of the image as a vertical line on the left.  When I de-select the layer, I can usually see a faint line where the ghost will appear in the export.  The third attached image shows the exported .png file - you can see a "ghost" line in the location of the left edge of the Placed photo.

BTW, I've noticed a similar behavior in the iPadOS version - that is not a beta copy, so this problem existed before the latest update.

 

 

[NotMyFault]

Hi, 

this smells like anti-aliasing effects at the edges, where you have partial transparent pixels, caused by projection.
It is possible to force them into 0 or 1, leading to a hard edge, but eliminating the wrong colors. 
try procedural texture filter with A=sign(A-b) and 0,1 input variable b set to about 1/2 (then adjust to taste). Copy and Nest this PT filter to every affected layer. 
 

 

 

[TexanInParis]

@NotMyFault

19 minutes ago, NotMyFault said:

this smells like anti-aliasing effects at the edges, where you have partial transparent pixels, caused by projection.
It is possible to force them into 0 or 1, leading to a hard edge, but eliminating the wrong colors. 
try procedural texture filter with A=sign(A-b) and 0,1 input variable b set to about 1/2 (then adjust to taste). Copy and Nest this PT filter to every affected layer. 
 

OK, I found the Procedural Texture filter, but I'm not sure what I need to set or enter.  You can see the color I'm using for the background in the lower left corner.

Thanks,

John

[NotMyFault]

Hi,

 

check my file below.

you can copy the PT filters from it and paste it into your file.

The "lupe" shows:

• black: alpha = 0
• white: alpha = 255
• red: 1 <= alpha <= 254

 

The "remover" boosts partial alpha to 255, based on the input parameter (use the slider to adjust).

 

ghost.afphoto

Edited May 14, 2021 by NotMyFault