Participant

Question

split image in equal halfs batch process

Forum|Forum|4 years ago
February 8, 2022
3 replies
1936 views

Hi all,

I have a project where I have to scan magazines and split the pages/scans right in half. (the magazines need to be put back together to its original state)

Is it possible to do that with the action command? I have 1000s of scans. Normaly a magazine consists of around 16 sheets that will be scanned duplex and need to be devided into 64 individual scans of a page (16x4=64)

One tricky thing though, de lenght of the pages varies, the front page is wider than the page in the middle of the magazine. The scanner has been set on detecting ''page end"

Enclosed a total scan and the desired right and left result as an example.

Thanks for the help.

Actions and scripting

This topic has been closed for replies.

Stephen Marsh

Community Expert

In the following screenshot, the 50% selection of the canvas width does not perfectly match the centre point of the scan:

If there is a consistent "offset" or "bias" this can be accounted for.

C

Christiaan23055425kgz7Author

Participant

A little offset is not a problem in general. Sometimes it is, and I do a manual correction. This happens when the printing is to close to the center. Due to sloppy cutting at the printers.

Idealy I like the folowing: the scanner scans one sheet, duplex. 2 scans are made. In each scan sits 2 "pages". The scan needs to be split.

In numbers: suppose a leaflet is been scanned. It's on pice of paper foulded in half. Frontpage (1), inside page left (2) inside page right (3) and back (4)

The scanner scans the following: frontpage (1) and backpage (4) as one scan and the other scan is inside left (2) and inside right (3).

After splitting both scans:

1000a (frontpage 1)

1000b (backpage 4)

1001a (inside left 2)

1001b (inside right 3)

The number 1000 is just a number. However the order is important.

The next scans of a magazine in the same order as above. With increasing numbers 1002a+b, 1003a+b etc...

Thanks for all the help!

Stephen Marsh

Community Expert

I have illustrated how this can be performed via an action. You can use Batch, Droplet, Image Processor or Image Processor Pro scripts to name a few methods of applying an action in bulk.

You have to account for the offset somehow, either accepting this as the price to pay for automation or overcome the issue with pre-processing or an interactive process when batching.

As illustrated in the action, it is also possible to name the left and right hand pages. You can run two separate batches for the front or back of the printed sheet.

A script can save out the layers with the filename + layer name. This can be recorded into the action or a separate script could be made so that an action isn't required.

Such a script can be found here, it is using PNG:

https://community.adobe.com/t5/photoshop-ecosystem-discussions/how-do-i-export-layers-as-png-without-loosing-the-size-and-placement-of-the-particular-layer/m-p/12734226

All of this can be automated or semi-automated as above.

Stephen Marsh

Community Expert

Is it just a case of splitting each scan exactly into two half's for a LHS and RHS? If so, a simple action+script combo should suffice.

You then mentioned splitting again to 16x4, so I'm a little confused as the sample was only left and right sides. If you could illustrate that would help.

Are there special naming conventions or file format options etc?

C

Christiaan23055425kgz7Author

Participant

If a magazine has 64 pages (1-64) than if the staples are removed 16 sheets of paper remain. 1 sheet contains 4 page numbers. In the 64 page case: the first sheet has page number 1, 2, 63 and 64. (1 and 64 on one side and on the other side 2 and 63) My scanner scans the top side and the bottom side at the same time. Hence to dubble scans. And both scans need to be split up to extract the individual pages.

The images above display 1 side of the original sheet.

Stephen Marsh

Community Expert

Ah... You confused me with the imposition info for saddle stitching, I thought that you wanted each half split again into more tiles. All good!

OK, so all you need is a left and right crop half from each image... What file format and options do you need? What file naming for each half? If the input scan was named:

myScan-0032.jpg

Would the following be acceptable?

myScan-0032_LHS.jpg

myScan-0032_RHS.jpg

You mentioned that a friend wrote you renumbering program so I'm not sure what you want or need.

Example before and after names would be helpful.

c.pfaffenbichler

Community Expert

I think this would effectively need a Script because saving the resulting files with some meaningful numbering or naming convention exceeds basic Actions.

Anoher issue: Did you black-back when scanning?

Because it seems like elements of the backside can be seen.

C

Christiaan23055425kgz7Author

Participant

No it's scanned with an old eqivalent of the fi-7700 scanner.

I have asked a friend to make a renumber program for me, and that works realy well. After the run all pages are in the correct order.

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