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View Full Version : Enlarging tips? (No, not that kind!)


umtutsut
05-27-2010, 09:13 AM
Gang,

Jan's great job on Mars Express -- which I'd like to build in 1/24 scale rather than 1/40 -- prompts me to ask for enlarging tips. (No male enhancement jokes, please! :p)

I've tried enlarging a couple 1/96 designs to 1/72 without success. I used Gimp to cut and paste parts of the design to a letter-sized canvas, which I then increased by 133%, but the lettering and details come out kinda fuzzy, even after sharpening. (Looks OK on the monitor, tho.)

I don't have a full version of Acrobat, nor do I have Photoshop. I thought there might be a way to PRINT part of the design(s) at 133% and then flip or somehow manipulate the printer properties to print the remainder at the bigger scale, but I can't figure a way.

Anyone have any advice?

:cool: Les (Friendly Airplane Asylum & ex-NASA flack)

cgutzmer
05-27-2010, 10:09 AM
Hello!
This would be Raster Vs Vector! Not everything will blow up and maintain the proper image quality you want. I think if you first expand each page to 133% then cut and paste from there to a new page it might look a bit better but in the end you might have to redo the model almost completely to get rid of the fuzzy.

Sorry but I always forget which one blows up better and which one does not...
Chris

cMags
05-27-2010, 10:13 AM
Vector is scalable, Raster requires software to kind of fill in the spaces between pixels when you enlarge.

Sometimes there's not a lot that can be done to scale up without re-doing graphics, because the detail isn't there. 33% is a large jump in scale. In your situation, going from 1:40 -> 1:24 is a 67% increase, even worse.

However, rather than using a scaling function, I would change the print resolution. Let me try to explain:

Say your original model is a raster image at 300dpi (dots per inch) which is a standard high-quality print resolution. If you were to instead print at 180 dpi, the print would be larger (167% of the original, the proper 67% jump you are looking for). 180dpi isn't as high quality a print, but still not bad, and if you use this process, you don't get the fuzzy computer-generated inbetween pixels.

To make the math a little more clear: At 300dpi, if your image is 3000 pixels tall, it prints to 3000/300 = 10inches. At 180 dpi, 3000/180 = 16.67 inches. There's your scale jump.

Now of course, you can't normally print a 16.7" page. This is where the cutting/pasting comes in.

So you take your original 300dpi page in Gimp. Now create a new page that's your paper size (I normally make a 8.0x10.5" page to give me 1/4" margins), at a 180dpi resolution. Now select one part (the largest one) and copy it from the original and paste it onto the new page. You'll see that it takes up more of the page. If your largest parts don't fit on a single page, you'll have to span them across multiple pages, but in general this technique will work. You can play around with arranging parts to save space on paper.

Hope that's clear. If you have any specific questions, let me know. By the way, this techique works great for scaling down too (you'd simply create a document with a higher resolution). Or, simply for saving cardstock. I often can re-arrange parts and save a whole sheet or two at the same scale, or when scaling down to my favorite 1:72 scale, fit the whole model, plus extra parts on a single sheet.

Lex
05-27-2010, 10:47 AM
Pixelation problem depends on what the original comes at, if the original isn't that crisp-clear then enlarging from 40 to 24 (less than doubling the size) wouldn't do much harm to texture quality, (in fact, barely noticable if standing from a distance normally used when viewing a 1:24 model... Or I need to change my glasses :D)

I find splitting parts up the main issue here. Not only does small inaccuracies (if there is any to start with) scale up with the model so they become more troublesome, but the requirement to split up big parts also creates additional problems - it's down to you to decide along which line it's the best to split the part. And else there are issues with paper thickness etc and thse are all down to the modeler to compensate for.

SCEtoAUX
05-27-2010, 10:59 AM
See if this will help in splitting a large image. It outputs to a pdf. I have used it to print out and assemble very large map images.

PosteRazor - Make your own poster! (http://posterazor.sourceforge.net/)

It is from SourceForge.net.

airdave
05-27-2010, 12:36 PM
See if this will help in splitting a large image. It outputs to a pdf. I have used it to print out and assemble very large map images.

PosteRazor - Make your own poster! (http://posterazor.sourceforge.net/)

It is from SourceForge.net.

If you don't know how to use a graphics program, something like this poster maker is a good option.
It fills in some of the necessary steps automatically, in creating the best possible larger image from a smaller resolution image.
However the program splits the image into sections with no regard for content or visual overlaps.
This can be a problem when producing paper model parts.
Ideally, parts should be positioned on pages with no breaks or seams.
This should only be a requirement for large parts that wouldn't fit on one page anyway.

You cannot add details, pixels, information to an image that isn't there.
So when you enlarge an image, you must enlarge the pixel details and enlarge the spaces between those pixels.
This will always result in a lower "resolution" and visually pixelated image.

The trick to enlarging any image, is to increase the pixel resolution before enlargement and attempt to clarify the image as much as possible.
This means smoothing, sharpening, colour contrasting, noise and moire removal, etc
to create the best possible looking image that can now be enlarged with better results.
Converting any image into a PDF for saving helps retain quality within that image as opposed to standard jpeg optimization which could eliminate all the clean up work you may have done to the image.

For paper model printing...you need to split up the parts of the model (once the enlargement steps are completed)
and re-arrange those parts into new printable pages.
this is the most time consuming part of the job.
And for this step, you are most likely going to need a proper graphics editing program.

cMags
05-27-2010, 01:08 PM
Well, looking at the model in question, Mars Express at: ESA - Space Science - Models (http://www.esa.int/esaSC/SEMEO5T1VED_index_0.html), it looks like the model consists of three pages of vector-lined parts with just a few areas containing somewhat poor raster textures (on the main body and a few other small boxes). All parts look like they'd fit on a single page at 1:24, with the possible exception of the main body. But this main body is a slightly deformed cube, so it has a nice natural split line if necessary.

Resizing and re-arranging the parts will either require a vector graphics program, such as Inkscape (free), or exporting a high-resolution raster image from the vector format and working in a raster program such as Gimp.

mbauer
05-27-2010, 02:14 PM
Vector is scalable, Raster requires software to kind of fill in the spaces between pixels when you enlarge.

Sometimes there's not a lot that can be done to scale up without re-doing graphics, because the detail isn't there. 33% is a large jump in scale. In your situation, going from 1:40 -> 1:24 is a 67% increase, even worse.

However, rather than using a scaling function, I would change the print resolution. Let me try to explain:

Say your original model is a raster image at 300dpi (dots per inch) which is a standard high-quality print resolution. If you were to instead print at 180 dpi, the print would be larger (167% of the original, the proper 67% jump you are looking for). 180dpi isn't as high quality a print, but still not bad, and if you use this process, you don't get the fuzzy computer-generated inbetween pixels.

To make the math a little more clear: At 300dpi, if your image is 3000 pixels tall, it prints to 3000/300 = 10inches. At 180 dpi, 3000/180 = 16.67 inches. There's your scale jump.

Now of course, you can't normally print a 16.7" page. This is where the cutting/pasting comes in.

So you take your original 300dpi page in Gimp. Now create a new page that's your paper size (I normally make a 8.0x10.5" page to give me 1/4" margins), at a 180dpi resolution. Now select one part (the largest one) and copy it from the original and paste it onto the new page. You'll see that it takes up more of the page. If your largest parts don't fit on a single page, you'll have to span them across multiple pages, but in general this technique will work. You can play around with arranging parts to save space on paper.

Hope that's clear. If you have any specific questions, let me know. By the way, this techique works great for scaling down too (you'd simply create a document with a higher resolution). Or, simply for saving cardstock. I often can re-arrange parts and save a whole sheet or two at the same scale, or when scaling down to my favorite 1:72 scale, fit the whole model, plus extra parts on a single sheet.

Always had trouble with the PDF files myself. Found that if I use the lower dpi, they seem to print better. Now I know why after 9-years of hair pulling!


Thank you, thank you!!!!!

Mike

Retired_for_now
05-27-2010, 08:14 PM
I've done a few enlargements from PDF - but this is strickly a stone-age microserf solution (I have no idea why it works - likely related to the more informed pixel discussion above).
Using the little zoom window in the Acrobat Viewer - I blast it up to around 400% or more. Then, using the snapshot tool (tools on top menu, select and zoom, snapshot tool) I select the part(s) and copy to the clipboard (right click, copy selected graphic). I then paste that onto a blank page in my ancient PowerPoint. If I don't change the Adobe zoom setting as I go back and forth, all the parts come across at a consistent scale. Once they are all pasted into PowerPoint, I select them as objects and resize them to the appropriate scale.
I usually don't have problems with the clarity of the enlarged graphic - if it looks OK when I zoom in it will generally be fine when pasted into the graphics program (see pixel discussions above).

Yogi (grunt, snort, me go back to cave now ...)

Just checked my copy of the Mars Express - the textures are pretty much pixelated and many of the curves segmented. Just by staring at the screen, I'd say you should get a reasonable result at 1:24 scale.

umtutsut
05-28-2010, 07:02 AM
Mucho thanx for the suggestions! I'll just have to try things to see if I can get a good result.

:cool: Les (Friendly Airplane Asylum & ex-NASA flack)