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Archiver > APG > 2008-09 > 1220285289


From: Michelle LeClair <>
Subject: Re: [APG] Scanning Letters
Date: Mon, 01 Sep 2008 12:08:09 -0400
In-Reply-To: <48BC02B8.5070404@debbiewayne.com>


A few more thoughts... This may be getting a little too involved but pieces
of these items are being brought up and this may help understand things
more.
* One thing to understand with scan size and dpi is that the two are
proportional. If the image size is 4x5 at 300 dpi in your original scan and
you want to blow it up to a 8x10 your output will only be at 150 dpi. As one
goes up by half the other goes down by half (if you go up in quarters then
the other goes down in quarters). Or vise versa, if you print it at 2 x 2.5
its dpi is now 600 dpi. Which is why a number of posts are telling you to
scan at higher dpis at your original scan so that you have flexibility later
on to print out at a larger size. Some image programs will NOT allow you to
set up your photos correctly. Make sure that you¹re not manipulating your
image in the wrong program that reduces your DPI (save a backup if you¹re
unsure).
* Also understand that some things you just can¹t change:
> * A monitor views anything at 72 dpi, you can scan an image as large as you
> want but your monitor can only see so many pixels at a time. The image will be
> larger in size but it won¹t enhance your view.
> * A book or magazine is always printed at a certain line screen (if you¹re
> ever placing an ad or writing you¹re own book, they¹ll tell you in their
> specification form), usually it¹s 133-150 lines per inch (lpi)
>> * You always want to multiply your line screen by 2 or 2.5 to get your final
>> dpi which is how that MAGIC number of 300dpi came about. If you scan an image
>> at 1200 dpi and it¹s 10² x 10² (just an example), and want to print it at
>> that exact size. It will NEVER really print at 1200 dpi. Now if you want to
>> print it at 40x40 at 300dpi then your good. Here¹s the math: 10x10 at 1200,
>> which is 20x20 at 600 dpi, which is 40x40 at 300 dpi.
>> * The same goes for photos, large format posters, etc. The printers of
>> whatever media can only go to certain limits. After that the extra dots are
>> wasted. A large format inkjet poster usually prints at 200 dpi, you can send
>> a 1200 dpi image to them but this will do 2 things, upset the pressman and
>> probably up your cost because of the time it takes to print (larger files
>> will take larger time to process)
>>> * I¹ve printed on soda cans, magazines, archival paper, billboards (which
>>> are actually only about 30 dpi as an FYI), sides of trucks, heck I¹ve even
>>> worked on the designs of footballs and basketballs, and a million other
>>> medias and no where has the final print ever been larger than 300 dpi at the
>>> FINAL output size.
* What Debbie points out is great, think about cropping a photo or part of a
document (a signature perhaps) or even scanning that separately at a higher
resolution.
* If you¹re scanning a document in black & white (b/w) line art mode that is
then considered the bitmap color formula I was speaking of early on. 600 dpi
is appropriate for this format at final size. You could use this format to
scan a b/w newspaper where you want to keep the letter forms as crisp as
possible. But realize there is no color data within this file. Sometimes I
scan these types of files as both color and b/w.
* Quick list of dpis at FINAL output size:
>> * Color photos off desktop printers: 200-300dpi
>> * Large format posters: 200-300dpi
>> * Magazine or Book: 300dpi
>> * Tshirt: 300dpi (some places may ask for less but you¹re good with 300)
>> * Banners: 200-300dpi


And you may not want to count out Mac users, there¹s many of us out there
and growing quickly. No viruses, no worms, no windows :)




Michelle LeClair
President
Creative Director
-----------------------
My Graphics Co., Inc.
PO Box 127
Chatham, NY 12037
518.392.5288
mygraphicsco.com

View t-shirt designs at MyGraphicTees.com!



From: Debbie Parker Wayne <>
Date: Mon, 01 Sep 2008 09:56:56 -0500
To: <>
Subject: Re: [APG] Scanning Letters

I'll add one other thing to Michelle's excellent advice. Think about how
you might want to use the image in the future, particularly if you might
need to enlarge a small portion of the image.

For example, when a client wanted to crop and enlarge just the faces of an
ancestral couple from a group photo to print on a reunion T-shirt, a 300dpi
scan of the fingernail sized faces was just not high-res enough to make a
good enlarged print.

Another example, on one of my photos I was able to use a very high-res scan
of a poster in a store window behind my ancestor to determine the day a
minstrel show was performing. I then viewed the newspaper microfilm to find
the year that minstrel show was performing on those dates. This helped me
date the photo of my ancestor. I could not do this with a 300dpi or 600dpi
scan. I needed much more detail.

If there is any chance you may want to enlarge a small section of a
photograph you may want to save at a higher resolution. If I am copying
small photos with multiple people I scan at 600dpi, 1200dpi, and sometimes
2400dpi, but never larger than the OPTICAL resolution of my scanner. This
makes a much larger file, but I don't have to get access to the original
again. And I don't have to worry the original may get lost in a hurricane
or tornado.

Optical resolution is the number of pixels per inch the scanner physically
records. Digital or interpolated resolution is usually a larger number, but
software will look at all the pixels and add information based on a
mathematical algorithm. The end result is not as good as if you scanned the
original at a high resolution.


Regards, Debbie

Debbie Parker Wayne
Wayne Research -- http://debbiewayne.com/
APG Lone Star Chapter -- http://lonestarapg.com/
Webmaster and Chapter Representative




Michelle LeClair wrote on 8/31/2008 1:52 PM:
...

> * keep the resolution (dots per inch or dpi) at least 300. You really only
> need 200 for a good print off most desktop printers but since you¹re
> probably never going to see these items again, and if at anytime in the
> future you want to print them bigger or in a book, you¹ll need that 300 dpi
> resolution
...

>
> Michelle LeClair





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