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Indexed - Creating a Pseudo mosaic using PS CC
Apr 30, 2021 14:45:48   #
Rongnongno Loc: FL
 
My wife wants to create a mosaic using many lavoirs images of hers.

Since she expects me to help her out and that I have never done that before I started to look onto it.

First I searched software to do it. I found some weird mosaic demos in the process. Something struck me, all mosaics seem to use an overlay image and use transparency to create the 'look'.

I watched a little software demo videos, did a search for the best out there and, well, PS CC came up on top.

The process seems simple:

Select images and place them in a separate directory for convenience, create a contact sheet, add an overlay image and away you go...

Well, not so fast. It is more complex than this. What I was looking out was 'pseudo mosaic creation', hence the thread title.

So that is it for this tutorial introduction.

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Apr 30, 2021 15:13:33   #
Rongnongno Loc: FL
 
Preparation:

Select the number of images with the mosaic in mind:
 ► Size of the mosaic (W*H) (Width*Height)
 ► Number of rows
 ► Number of columns
 ► Number of images per row
 ► Total images needed = (# per row) * (# of columns)
 ► Image orientation
→ The images' orientation is important as if they do not have the same (orientation) PS CC will adjust down all the images compared to the highest one and create an unwanted margin. In this case either discard it as a tile or crop it to horizontal. Rotating the image 90 degrees is another solution, but it might look weird.

Each image must be sized using the ratio created by the choices made above.
  ► W of a tile (Wt) = W/Columns
  ► H of a tile (Ht) = H/rows
  → You can resize to a multiple value as long as the images keep the same Wt/Ht ratio.

Preparing the images: (Warning, using another software to resize)
 ► To avoid issues with margins it is best to resize all the images. They should be identical in pixel size
This can be done individually (it will take a long time to crop/resize) or using a second software like I do.
 ► I used ACDsee to resize down the image horizontally, keeping the aspect ratio.
Still using ACDSee I resize down one more time using the smallest vertical edge. This time I do not use proportional.
 ► Using ACDsee I create a thumbnail view of the mosaic by reducing the size of the thumbnails until I have the came number per row as I would in the mosaic.
 ► Once organized as to where I want the images to be I use batch rename to have a sequential naming that will be reflected in PS CC and force the sequential position of all the images per row and per column.



→ LR can create a contact sheet under the print menu. Is it editable??? I have no clue how to use LR, sorry.

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Apr 30, 2021 20:59:58   #
Rongnongno Loc: FL
 
Notes:
Create groups
Expand canvas
Use an image or design as guide (create a mask from it and disable it)
Work per group to select tiles (make a duplicate)
Drag drop tiles over the guide
When the guide is covered make a selection from the mask.
Delete what is over?
Revert the back and lower darken?

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May 1, 2021 03:46:32   #
Rongnongno Loc: FL
 
Mosaic Planing instruction:
Mosaic size in inches *
Width 72 (21600px)
Height 36 (10800px)
(Ratio 2/1)
Resolution 300px/inch
Order of creation: Row, left to right
Column 10
Rows 10
(Ratio 2/1)
Total tiles 100
Tile minimal size
Wt = 2160x
Ht = 1080px
Spacing = 0

Tile size ratio Wt/Ht 2/1

* Since the images will be reduced, to limit the initial damage using a large canvas is desirable but not an absolute thing to do.

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May 1, 2021 03:50:52   #
Rongnongno Loc: FL
 
Tile preparation

Note I use ACDSee.

If you want to do it right you must adjust every tile so that they have the same luminosity then crop them using the Wt/Ht ratio (in this case 2/1)

Using your image, select the smallest (width) Keep the proportions
Adjust all your images to that width
Divide the width by 2 to get the height ratio 2/1
Apply the height to all the image DO NOT keep the proportions.
ACDSee allows both at the same time, if you use this program. Just set the width and height and disable keep proportion.

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May 1, 2021 09:52:57   #
Rongnongno Loc: FL
 
PS CC Preparation

Creating a contact sheet
File
Automate
Contact sheet



Instructions:
► Blue arrows:
  → Set the mosaic size. Create it as large as you dare. The tiles created are not smart objects so if you need to edit a tile it will be nearly impossible unless the size is 'large enough' (you can transform them later on thought).
  → Set the rows and columns
► Yellow arrows
  → Make sure the three check box are unchecked.
  → If the images are flattened you will not be able to move the tiles
  → Rotate for best fit left unchecked allows you to immediately see if there is a tile orientation issue
  → Do not use auto spacing. Period.
► Red arrows
  → PS CC will refuse to enter a value of zero if you are creating the image in Pixel.
  → Switch to Inches or centimenters to enter '0'
  → Using pixels, enter 0.1 or .01. PS CC will then round the number to '0'

► Green arrows
→ Select where and how to select the images that will become tiles
→ If you have more tiles than needed this will create a second PS CC document...
→ You can cancel the process using the cancel key. A partial contact sheet will be created.

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May 1, 2021 10:38:00   #
Rongnongno Loc: FL
 
PS CC preview



The mosaic as seen when first created.

The red arrow points at white lines that are present when the images is used in low resolution (fit screen)
The yellow arrow points to each tile created as a layer and positioned as well as the mask used.

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May 1, 2021 11:01:55   #
Rongnongno Loc: FL
 
Last step
Add an image or text as an overlay to simulate a complex mosaic.



Process:
Created a tile group to get an uncluttered workspace.
Added a spider, edited out most of the image (mask), positioned it in the lower left corner
Adjusted opacity down
Added the text just because

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May 1, 2021 11:10:33   #
Rongnongno Loc: FL
 
Final result


(right-click and open in new tab)

I will link this scaled down image to a larger zoomable one later on...
The saved size, 100% PNG, is 402MB...

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May 1, 2021 11:21:59   #
Rongnongno Loc: FL
 
Now why is this a 'pseudo' mosaic?

A correctly created mosaic uses an overlay as a guide to create a tile shape then the overlay is removed leaving only the mosaic to display the intended image.

Can this be used to create a real mosaic?
Yes, because all the tiles can be moved/edited at will.
The process will be relatively involved to make this a true mosaic:
All tiles must be transformed into a smart objects in order to edit them and keep them 'safe'.
You must create guides lines or a custom grid in order to move the tiles in proper place
The canvas must be doubled in order to either create a scratch pad or a new image (Note that the numbers of row guideline is then multiplied by two)
For convenience’s sake group the tiles by....

That could be a really involved tutorial. This one is simple in comparison.

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May 1, 2021 11:50:06   #
Rongnongno Loc: FL
 
For info:
This is the first time I use PS CC to do this.

Creating a true mosaic is not for the faint-hearted.
Each tile must be carefully prepared even before being used. Consider that there might be a few hundreds if not thousands of them...
Then the creation of the canvas itself is easy but filling it with tiles involves more than resizing and placing them.
Mixing orientations AND rotation can be desired to follow the overlay guideline as well as creating masks when needed to alter an area opacity or tint...

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