Scanning DPI

[El Cheapo]

What is the best setting for decals, fins, etc to scan into computer. Is there one setting to scan it at actual size. I tried using 300dpi and it's far too big.

 

[Peartree]

If I'm trying to send it to someone then it needs to be smaller but if I want to copy a decal then (if I can) the scan rate needs to equal or exceed the dpi of the printer I'm printing on.
[edit] Please note that I haven't done lots of this and others have certainly done far more, even so it seems like a good rule.

 

[troj]

What is the best setting for decals, fins, etc to scan into computer. Is there one setting to scan it at actual size. I tried using 300dpi and it's far too big.

That's likely because you're taking a 300 DPI scan and viewing it on a 72 DPI device -- your monitor.

Unless the software you're using to view it understands dimensions in terms of units other than pixels, you'll have this problem.

You can also potentially run into problems when you print, unless what you're using to print A) can deal with physical dimensions instead of pixel dimensions, and B) can be told not to scale to fit.

-Kevin

 

[Lentamental]

300 is most definitely not too much. 600 is getting there, and you can't really expect to do anything more if you have large decals that you are scanning. Then again, I am a photographer, so I have rather elevated standards.

Remember however, that your printer has a maximum printing resolution, and you should never scan anything at less than this resolution. To get even better results, try to scan at a resolution that is a multiple of the maximum resolution of the printer, so that it scales nicely (don't scan at 250dpi if the printer prints at 240dpi). If your printer prints at nonstandard resolutions, then just scan as high quality as you can.

You can always shrink the image down, and lose data, but once you scan the decal, you can never gain data.

 

[Micromeister]

My printers have a maximum dpis of 300 epson and 600 Alps, so I generally produce my decals in corelDraw and scan existing decals at 600dpi.

Keep in mind you can always reduce the image dpi before you print without effecting the quality but you can't increase a low res scanned image. Scan at the highest resolution our PRINTERS well reproduce.

another useful hint: Save your scans or Drawings on flash drives or other mass storage unit(s) to keep the computer running at top speed.

 

[jadebox]

A rule of thumb (ala Nyquist) is to sample at no less than twice the desired resolution to avoid aliasing. If your printer prints at 600 dots per inch, try to scan at 1200 DPI.

-- Roger

 

[El Cheapo]

Thanks, guys. I'm getting it figured out. BTW, I'm using a Kodak ESP 7 All in one printer

 

[jadebox]

The images will look really large on your computer display. A typical display is about 1200 pixels wide, so, if you scan the decal at 1200 dpi, you'll see just one-inch of it on the screen at 100% zoom.

And the files will be rather large. Many scanners save images as TIFF files by default. These files tend to be large because they aren't compressed (or aren't compressed as much as typical image files). This is good because the saved image doesn't suffer any artifacts caused by compression. It's bad because the files are huge. You can decide to save the images as JPG files. In this case the files will be much smaller. But, JPG is a "lossy" compression method, so some detail may be lost. I don't think that will be a problem, though.

Another thing is to try the different modes offered by your scanner software to see what works best. If the software has an option for "color line art" then that would probably be the best choice, but you might try other color modes to see how they work. Be aware, that some software changes the scan resolution when you change the mode, so you may have to go back into the settings after changing the mode to make sure the resolution is still what you want.

-- Roger

 

[troj]

You can decide to save the images as JPG files. In this case the files will be much smaller. But, JPG is a "lossy" compression method, so some detail may be lost. I don't think that will be a problem, though.

JPG is actually a bad format for this type of work -- because it's lossy, it suffers from compression artifacts, especially in areas of solid color. It can easily result in "muddy" or "blotchy" areas in the resulting image.

GIF and PNG are much better formats, if you want to use compression, as both are lossless.

-Kevin

 

[jadebox]

JPG is actually a bad format for this type of work -- because it's lossy, it suffers from compression artifacts, especially in areas of solid color. It can easily result in "muddy" or "blotchy" areas in the resulting image.

GIF and PNG are much better formats, if you want to use compression, as both are lossless.

Good point. GIF is limited in the number of colors it can represent, but that should be okay for decals. PNG is sort of the "everything" format, but isn't as well supported as GIF and JPG.

-- Roger