The size of a file make a 20" X 30" poster?

Started May 10, 2004 | Discussions
henryyao
Regular MemberPosts: 119
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The size of a file make a 20" X 30" poster?
May 10, 2004

I am wondering if I want to get 20" X 30" enlarged poster, what digital size (in terms of pixels) of my file do I need? For instance, I have taken a picture with Canon G3 with max. resolution (4 MB pixel). And after slight adustment with PS 7.0, I saved it as tiff file. I would like to make a 20" X 30" poster out of it, but I have heard and read about that 4 MB-pixel file can only be blowed up to 11" x 14" or less with good sharpness. Thus, I am not sure whether my file is enough to make a 20" X 30" poster with nice sharpness? Anyone can help me here?

William Carter
Regular MemberPosts: 260
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Re: The size of a file make a 20" X 30" poster?
In reply to henryyao, May 10, 2004

If you know your required dpi (say 300) and know the print size desired (20x30), then you have to just figure out what size file is required to produce a print that size at that dpi. There's some algebraic way to express this, but since math isn't my strong suit, I don't know what the formula would be. Nonetheless, working backwards, you'd need a file that's 154Mb. (I just created a new black doc in Photoshop and plugged in the 2 numbers I knew -- print size and dpi).

Whether you can interpolate a G3 file up to this size and retain good quality is another question. I've interpolated a nikon D100 file (6 megs) up to a 20x30 print size and it looks greta. But not all pixels are created equal.

henryyao wrote:

I am wondering if I want to get 20" X 30" enlarged poster, what
digital size (in terms of pixels) of my file do I need? For
instance, I have taken a picture with Canon G3 with max. resolution
(4 MB pixel). And after slight adustment with PS 7.0, I saved it as
tiff file. I would like to make a 20" X 30" poster out of it, but I
have heard and read about that 4 MB-pixel file can only be blowed
up to 11" x 14" or less with good sharpness. Thus, I am not sure
whether my file is enough to make a 20" X 30" poster with nice
sharpness? Anyone can help me here?

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William Carter
Regular MemberPosts: 260
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Re: The size of a file make a 20" X 30" poster?
In reply to William Carter, May 10, 2004

I mean to say "I just created a new BLANK (not black) doc in Photoshop and plugged in the 2 numbers I knew -- print size and dpi)."

William Carter wrote:
If you know your required dpi (say 300) and know the print size
desired (20x30), then you have to just figure out what size file is
required to produce a print that size at that dpi. There's some
algebraic way to express this, but since math isn't my strong suit,
I don't know what the formula would be. Nonetheless, working
backwards, you'd need a file that's 154Mb. (I just created a new
black doc in Photoshop and plugged in the 2 numbers I knew -- print
size and dpi).

Whether you can interpolate a G3 file up to this size and retain
good quality is another question. I've interpolated a nikon D100
file (6 megs) up to a 20x30 print size and it looks greta. But not
all pixels are created equal.

henryyao wrote:

I am wondering if I want to get 20" X 30" enlarged poster, what
digital size (in terms of pixels) of my file do I need? For
instance, I have taken a picture with Canon G3 with max. resolution
(4 MB pixel). And after slight adustment with PS 7.0, I saved it as
tiff file. I would like to make a 20" X 30" poster out of it, but I
have heard and read about that 4 MB-pixel file can only be blowed
up to 11" x 14" or less with good sharpness. Thus, I am not sure
whether my file is enough to make a 20" X 30" poster with nice
sharpness? Anyone can help me here?

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Robert Sheldon
Senior MemberPosts: 2,017
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Re: The size of a file make a 20" X 30" poster?
In reply to henryyao, May 10, 2004

You would need about a 4500 X 3000 file. This assumes 150 dpi for printing which is acceptable for a large print. You could start out with something a little smaller. There are some programs (Genuine Fractals is one) that do a good job of up-sizing.

Bob Sheldon

henryyao wrote:

I am wondering if I want to get 20" X 30" enlarged poster, what
digital size (in terms of pixels) of my file do I need? For
instance, I have taken a picture with Canon G3 with max. resolution
(4 MB pixel). And after slight adustment with PS 7.0, I saved it as
tiff file. I would like to make a 20" X 30" poster out of it, but I
have heard and read about that 4 MB-pixel file can only be blowed
up to 11" x 14" or less with good sharpness. Thus, I am not sure
whether my file is enough to make a 20" X 30" poster with nice
sharpness? Anyone can help me here?

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tim g
Contributing MemberPosts: 597
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Re: The size of a file make a 20
In reply to Robert Sheldon, May 11, 2004

I use a Canon s400 4mp camera and routinely print 13X19 prints from it. I have not tried any larger as that is all my printer allows. The Canon easyprint software and Qimage do a good job of interpolation and making the relatively small pics look great. I am not sure you could push it that much further, but it should not cost that much to try one and see. I'd be interested to hear your results if you do give it a whirl.
--
Tim G
s400, i9100 and some other stuff

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Greg_E
Veteran MemberPosts: 4,121
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Re: The size of a file make a 20" X 30" poster?
In reply to henryyao, May 11, 2004

henryyao wrote:

I am wondering if I want to get 20" X 30" enlarged poster, what
digital size (in terms of pixels) of my file do I need? For
instance, I have taken a picture with Canon G3 with max. resolution
(4 MB pixel). And after slight adustment with PS 7.0, I saved it as
tiff file. I would like to make a 20" X 30" poster out of it, but I
have heard and read about that 4 MB-pixel file can only be blowed
up to 11" x 14" or less with good sharpness. Thus, I am not sure
whether my file is enough to make a 20" X 30" poster with nice
sharpness? Anyone can help me here?

I have made several 12x18 prints from a 2.1MP image, but 20x30 might be a little large for a 4MP image. And a few 20x30 from 7.7MP images. Alot might depend on the content in the image.

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henryyao
Regular MemberPosts: 119
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Re: The size of a file make a 20" X 30" poster?
In reply to henryyao, May 11, 2004

henryyao wrote:

I am wondering if I want to get 20" X 30" enlarged poster, what
digital size (in terms of pixels) of my file do I need? For
instance, I have taken a picture with Canon G3 with max. resolution
(4 MB pixel). And after slight adustment with PS 7.0, I saved it as
tiff file. I would like to make a 20" X 30" poster out of it, but I
have heard and read about that 4 MB-pixel file can only be blowed
up to 11" x 14" or less with good sharpness. Thus, I am not sure
whether my file is enough to make a 20" X 30" poster with nice
sharpness? Anyone can help me here?

Thanks everyone for help. I guess I will hold on to it. But at least, I will try 13 X 19.

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Chris R-UK
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Re: The size of a file make a 20" X 30" poster?
In reply to henryyao, May 11, 2004

henryyao wrote:

henryyao wrote:

I am wondering if I want to get 20" X 30" enlarged poster, what
digital size (in terms of pixels) of my file do I need? For
instance, I have taken a picture with Canon G3 with max. resolution
(4 MB pixel). And after slight adustment with PS 7.0, I saved it as
tiff file. I would like to make a 20" X 30" poster out of it, but I
have heard and read about that 4 MB-pixel file can only be blowed
up to 11" x 14" or less with good sharpness. Thus, I am not sure
whether my file is enough to make a 20" X 30" poster with nice
sharpness? Anyone can help me here?

Thanks everyone for help. I guess I will hold on to it. But at
least, I will try 13 X 19.

For a 20"x30" you are going to have a resolution of about 75-80 PPI. You could always crop out a 4x6 at this resolution and print it to see what a 20x30 would look like. Remember that when you are looking at a 20x30 you will normally be standing 2-3 ft away, not close up as you would with a 4x6.
--
Chris R

 Chris R-UK's gear list:Chris R-UK's gear list
Canon EOS 7D Panasonic Lumix DMC-GF1 Panasonic Lumix DMC-GH2 Panasonic Lumix G Vario 14-45mm F3.5-5.6 ASPH OIS Canon EF 50mm f/1.8 II +6 more
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WiseWilliams
New MemberPosts: 11
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Re: The size of a file make a 20" X 30" poster?
In reply to henryyao, May 11, 2004

henryyao wrote:

I am wondering if I want to get 20" X 30" enlarged poster, ... For
instance, I have taken a picture with Canon G3 with max. resolution
(4 MB pixel). And after slight adustment with PS 7.0, I saved it as
tiff file.

I have used my Canon G2 extensively to make 20" x 30" enlargements through ofoto.com and have been pleased with the results.
--
b r i a n . a . w i l l i a m s

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jack scholl
Senior MemberPosts: 2,783Gear list
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Re: The size of a file make a 20
In reply to henryyao, May 11, 2004

Just received a 20"x30" print from ezprints.com from a 4mp Panasonic FZ10 file. Upsized in PS to 54mb (max you can upgrade to ezprints). The print was spectacular. There were some pixels on the edges of high contrast edges showing from about 12'. At 2' it was mountable and breathtaking. The detail just amazes. Kudos to Panasonic and ezprints.
Jack
http://www.pbase.com/jrs40

henryyao wrote:

I am wondering if I want to get 20" X 30" enlarged poster, what
digital size (in terms of pixels) of my file do I need? For
instance, I have taken a picture with Canon G3 with max. resolution
(4 MB pixel). And after slight adustment with PS 7.0, I saved it as
tiff file. I would like to make a 20" X 30" poster out of it, but I
have heard and read about that 4 MB-pixel file can only be blowed
up to 11" x 14" or less with good sharpness. Thus, I am not sure
whether my file is enough to make a 20" X 30" poster with nice
sharpness? Anyone can help me here?

 jack scholl's gear list:jack scholl's gear list
Sony a6000 Nikon 1 V3 Sony DT 16-80mm F3.5-4.5 ZA Carl Zeiss Vario-Sonnar T* Sony 70-300mm F4.5-5.6 G SSM Sony E 18-200mm F3.5-6.3 OSS +6 more
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