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Etching your own copper panels #3: Making the Image Mask

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Blog entry by splintergroup posted 10-31-2016 06:16 PM 873 reads 0 times favorited 4 comments Add to Favorites Watch
« Part 2: Process Summary Part 3 of Etching your own copper panels series Part 4: Applying the Resist »

Welcome back!

Please post a comment if there is anything you want clarified or if you have any questions/comments.
At the end of the following posts on the actual process, I’ll add a section on alternative methods/materials where appropriate. I also will try to include links to material sources and further info on techniques. Hopefully these links will stay around!

The whole process begins with the image you want etched into the copper. This image can be most anything!

The restrictions are that the image must be able to be used when converted to black/white (there can be no grey).
In the good old days with newspapers and fax machines, grey was represented by a field of black ‘dots’ on top of a white background. More/bigger dots made the area darker, fewer/smaller dots made the area lighter. The eye interprets this as shades of grey and you can attempt this with the etching of the PCB panel, but I’ve never tried it.

Lets keep it simple!

The Mask
The mask is used to protect some areas of a photo-resist covered copper panel and expose other areas to the UV light.
For the negative resist I am using, the areas that I want as copper are the ‘clear’/non-black areas on the mask.

I am making some copper panel inserts for a few playing card boxes I have planned. I want to use the ace of spades card image since it is fairly traditional, but I want to add a different design to the card center. These boxes are going to be sold at the local gift shop, they say people seem to want something with ‘Kokopelli’, I will oblige 8^)

Equipment
I use Photoshop and/or a simple drafting program (macDraft). The operations I’m doing are very basic and you can usually do these with the photo/drawing apps that come with every computer nowadays. You can also do a cut/paste job and use a copy machine (see “Alternatives” at the end of this post).

When I made my clock dial face. I drew a circle with my drafting program that was the same as the sweep of the clock hands. I then drew radii from the center mark to intersect the circle at each hour. I typed in an hour numeral at each intersection, then deleted the circle and radii lines, leaving only perfectly placed hour numbers.

The Background Image

I needed to start with a card. I only plan on keeping the ‘pips’ in the corner so I wanted to select the image based on those details:

Since my copper piece is going to be added as a panel to the box lid, I needed it oversized. My required dimensions are 4.125” H x 3.125” W. A standard playing card is 3.5” H x 2.5” W. I created a “canvas” with the larger size to work on, basically it is a border the same size as my panel to help with alignment later in the process. You can do the job without even considering this if need be.

Step one is to erase the large “Ace” in the center of the card and eliminate those edge lines. I also want to make sure this card image is standard size (3.5” x 2.5”) and a good resolution for my printer (600 DPI)

The Central Figure
Kokopelli, the freak is everywhere! 8^)

Anyhow, this is the one I chose, scaled to fit well on the previous image. (LJ’s seems to auto scale so it will look larger than it really is).

The Merging
I placed the Kokopelli onto the card, flipping the Kokopelli over so it would fit better between the ace pips. I also “inverted” the image (created a negative) because I wanted the image in copper with the background being the color of the PCB fiberglass core (black). The border is the larger 3.125”x4.125” area I need for my panel. The image is true black/white because I chose to “threshold” it to wipe out any grey areas.

The Final Image
I flipped the image again. I want the toner on the transparency film to be as close to the panel surface as possible. This makes the edges and detail on the copper as crisp as possible.

That’s it!
Now I print to out onto transparency film for the production mask. I have my laser printer set to maximum contrast.

Since my copper panel blank is the same size as the black area, I can easily align the two up when placing the mask onto the panel. You can also cut the image out with scissors to the same size as the blank and just align it directly. Any scratches or holes in the black areas will leave copper on the finished panel. These can be touched up with a black marker if needed.

I’ll show the panel prep with resist next and you’ll see some more details on the image/mask in the exposing.

Alternatives
There are literally 100’s of ways do do this entire process, I encourage you to search the topic and watch videos. This is the method I currently am using and with all photographic methods you will need to create this mask (either a negative or a positive).

A simple way to create the mask without a computer would be to take a playing card, tape some white paper over the areas you don’t want to see. then place your center image on top. Take the card to a copy shop and have them print to onto a transparency film with the best blacks possible.
If you have a computer and the basic photo software, you can probably save the final image onto a flash drive and have the copy shop print from that. Hand drawn art can be scanned on a flat bed scanner then printed (or directly on a copier).



4 comments so far

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Mean_Dean

6559 posts in 3171 days


#1 posted 10-31-2016 10:08 PM

Two areas that are stumbling blocks for me:

I’m interested in A&C clock faces—where would I find them?

Printing on transparencies—will my regular Canon inkjet printer print on them? And where do I find the transparencies?

I’m enjoying this blog series—thanks!

-- Dean -- "Don't give up the ship -- fight her 'till she sinks!" Capt James Lawrence USN

View splintergroup's profile (online now)

splintergroup

2073 posts in 1246 days


#2 posted 11-01-2016 02:57 PM

Dean, your ink jet should work fine (check the manual or Canon web site to be sure). A quick search for “inkjet transparencies” shows them available everywhere, even places like Walmart. I’d imagine some of the copy or office supply places might even sell them by the sheet.

As to the A&C clock faces, another quick search for “arts and crafts style clock face” turned up a site with plenty of examples. Hit the search engines “images” link and you’ll get more clock face pictures then you can shake a stick at.

When I lay out something like a clock face, I usually try to identify what makes the style. Typically this is the font used for the numbers and often the design of boarders etc.

Consider this reference image:

It has a designers watermark, but if you look at the font, it is very arts/crafts – ish. There is a website some free A&C font libraries I have used.
The clusters of squares in each corner and geometric lines are another characteristic.

Picking bits and pieces is a great way to composite your own design.

View Mean_Dean's profile

Mean_Dean

6559 posts in 3171 days


#3 posted 11-01-2016 09:04 PM

Thanks for all the great, useful links! I will bookmark this blog series, so it’ll be handy when I’m ready to do some clock faces.

-- Dean -- "Don't give up the ship -- fight her 'till she sinks!" Capt James Lawrence USN

View splintergroup's profile (online now)

splintergroup

2073 posts in 1246 days


#4 posted 11-01-2016 09:12 PM

You are welcome Dean, PM me if you need more info or any help.

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