Make your own PCBs form A to Z
using Eagle Layout Editor + Photoshop
author: Hlias Hliadis
(page 2/3)

Processing in Photoshop

Open Photoshop and click Open, find file BlinkLed.bmp and click Open, the program will open the PCB you created using Eagle.

 

As you can see the PCB traces are white and the empty space is black, that must be inverted because we want to print out the traces.

To achieve this we use the Invert command, click on Image – Adjustments – Invert or use the shortcut keys CTRL+I on your keyboard.

Right away the colors will be inverter and we now have the traces in black and the empty space in white.

As you can see there is an empty white space to the top of the image that is drossy and aggravate the file size , we can eliminate this using Crop Tool   from the tool bar, select the tool, move cursor to the upper left corner, click right mouse button and drag up to the lower right corner of the image so the drossy space left out of the selection.  Now the useful part of the image is normal and the white space became gray. Now double click to the normal section on press Enter to remove the drossy paper.

If you wish you can fill the white spaces with black to make a more professional look PCB. To achieve this we must convert the image to Grayscale and create a new Layer. Click on Image – Mode – Grayscale, and the menu Grayscale will show up. To Size Ratio give value 1 and click OK, then click to Layer – New – Layer or use Shift+CTRL+N shortcut from your keyboard.

Creating a new Layer is very important, for the reason that we don't affect the original design and we can restore it to the previous state if we want to.

With the creation of the Layer you will see to the Layers box that you have  Background which has a lock and Layer 1.

Click  to Layer 1 and select the Paint Bucket Tool   select as main color black:

Next click into the design, it will become black, but don't be afraid this is going to change in a while!

Now, double click to Layer Background, and the dialog box New Layer will open and then click OK.

You will see that Background now renamed to Layer 0 and the lock disappears, now click and hold the left mouse button to   Layer 1 and drag it under Layer 0, you must be able to see the original design.

At this point we must see some common functions of Photoshop so we can make our lifes easier. Photoshop was selected because is the best program - in my opinion - of it's category, has many facilities on operation, can read PDF files (Elektor gives PCBs in PDF format) and has the best image quality.

You must beaten using Zoom function, Polygon Lasso Tool and Hand Tool. Zoom can be easily controlled  with CTRL+ [Zoom in] – CTRL- [Zoom out],  Hand tool is used to move into the image to the section we are interested, holding Space and left mouse button, we move the image to the work area (Attention, Hand tool moves the image in the work area, that means that is replaces scroll bars, but Move tool moves the image of the Layer), Polygon Lasso tool is used pushing L, Lasso with the help of  Shift button can create horizontal straight lines, vertical and diagonal. You must always finish the Lasso tool to the point it started so it makes a closed loop (like the image below. Experiment with the tools to habituate with their operation. it's better to create a copy of the design so the prototype so you always have a untouched copy, click Image – Duplicate.

Click on Layer 0, Zoom to image 200%, move it with the Hand Tool, select Lasso tool, click near a PCB trace holding  Shift key and drag the mouse in the direction of the trace. Follow a go-around to close the loop at the point you started. If you want to move the image use Hand tool.

 

The section you selected in now in a discontinuous line, this section must be filled with black color, to achieve that select select the background color to black  and then press Delete key.

Repeat the operation to fill all the section you want to be black and finally the PCB will look like this one:

The “filling” could be achievement using Eagle with a Script, but the company that develops Eagle hasn't included a Script like this yet and the user's scripts have many glitches, so we prefer Photoshop to have more flexibility processing our design.

Save the image in PSD  format (Photoshop Format ) to be able in future to make any changes.

Now we will open an Elektor's PDF pcb file to process it using Photoshop.

For our example we use a file from the English site of Elektor, in the free category MiniProjects Online, we selected Led Christmas Decoration.

At webpage there is the word more… that links to a PDF file, this PDF must be downloaded (right click "save target as") to you pc.

After you have this file on your hard disk you must open it with Photoshop CS, click Open – File and open the PDF file.

The PDF Page Selector will show up, Inside this you can see the pages of PDF file, we need the one with the PCB layer that's on page 2, click on page 2 and OK.

Now the Rasterize Generic PDF Format dialog box will appear.

At Resolution field you must give the same value as our design has , (if you don't need to attach another PCB file then give a value between 150 and 600 dpi) at this example put 300dpi and click OK.

The file will open in Photoshop's working area.

We must remove any schematic, text and layout we don't need using Crop tool. Select the PCB area and click Enter. Now only the PCB remains.

This PCB must be printed two times for the construction and let's assume we want to make this construction twice. That means we need it four times.

To reproduce the PCB 4 times, we must change the paper size to our original design to Α4, Α4 measures 21*29,7cm (Width: 21 – Height: 29,7), click on Image – Canvas Size… menu

Put values Width: 21 – Height: 29,7 in cm and click OK, now the paper has Α4 dimensions.

At Layer bar there is Layer 1 and this is the Layer we must reproduce, to achieve that click CTRL+A and you will se to the borders of the paper discontinuous lines, then click CTRL+C to copy the Layer to the computer's memory, now click CTRL+V 3 times and you will se at Layer bar 3 Layer more (Layer 2, Layer 3, Layer 4), with Move Tool arrange the layers  to the page. The page must look like this one:

The empty space we left at the bottom will be used to add the PCB we created with  Eagle Layout.

Open the PCB we made with Eagle to BlinkingLed.PSD file, make a duplicate copy and close the original one. Click on layer menu and select Merge Down ή CTRL+E, you will see Layer 1 and Layer 2 to merge and finally only Layer 1 exists.

Click and drag in Layer bar Layer1 on top Elektor and the Eagle PCB will be added to Elektor's pcbs page along with Layer 5 to the Layer bar, with Move Tool move Layer 5 to the desired destination.

The PCB we created in Eagle is smaller than the Elektor's one but if you retain the Resolution then you must don't scare if you see it smaller. At this point make a test print on Α4 page to see if everything is printed out correctly and try to fit a component on top of the page to see if the scale is the right.
 

Exposure, Development, Etching >>
 

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