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Converting bar code to CMYK "True Black"


Question

I have .tiff. Part of the .tiff is a bar code. My printer is insisting the bar code be converted to 100%K - CMYK "pure black". (Their words)

A couple obstacles:

  1. The Bar Code has been scaled up. Since it got resampled in that process, the edges aren't pure black anymore. Just selecting the black area by color is tricky now, since the outermost pixels might or might not be included.
  2. The .tiff is in RGB8, and my printer wants CMYK. RGB rich black does not translate to 100% K in CMYK.

How would you go about changing this one part of the image to 100%K CMYK, to make the printer happy.

2016/03/06
1
4
3/6/2016 9:19:00 AM

Accepted Answer

The easiest way would be to create a selection around the bar code (I assume it's got the white background), then using the Channels Panel -

Hightlight the black channel and use Levels to boost the tone to 100%. Then Highlight the C channel and fill the selection with white. Then fill the selection on the M and Y channels with white as well.

Double check the K channel again and ensure the values are 100%.

That should give you only a 100%K bar code.

The preferable method is really to use a vector bar code. There are several online barcode converters which provide downloadable .eps files. Here is a link to a good one.

2012/02/09
8
2/9/2012 12:59:00 AM

An oldie but goody.

Part of the .tiff is a barcode.

Ouch... Well, we do not know about the final resolution of the file, the color mode of the barcode but there are potential problems here.

The Bar Code has been scaled up.

Dam. The potential problems are not potential anymore! They are here.


Depending on the real size of the barcode part, it can work or it is totally useless.

Using a TIF file implies that you are doing (or they did) the layout on the wrong program.

Let's assume the resolution is decent (we would need to analyze the number of bars, the type of code, the total pixels of the section and see how many pixels are making each bar and white space, besides checking the lineature of the output file)


Option 1

  1. Convert the RGB file to CMYK.

  2. Make a selection of the barcode and simply play with the curves or levels. Eliminate any CMY trace and darken the barcode in the K channel.

Option 2

  1. Cut the barcode.

  2. On the layout program simply paste a grayscale version of the image, with some adjustings in the levels. The same as option 1 but with only the grayscale channel.

Option 3... The correct one

Make the barcode again and use a layout program to insert it as vectors.

Making a barcode 100% K implies two things.

A. is made of only one ink (not necessary black)

B. It is not screened.

Here is an image of what do I mean by screening.

enter image description here

If the barcode is big enough this screening will have little effect on how well it is scanned...

But I really doubt you want a barcode really big... so make in vectors.

2018/04/25