Hey can someone answer a question I have about photoshop?

The question is how do I enlarge the image but still maintain the image's resolution. Say I want to enlarge the image from 2 inches to 10 inches but the resolution keeps getting worse as it gets larger (i know it's because they are adding more pixels as it gets larger). But is there anyway in photoshop to enlarge a picture but still maintain the same resolution? If not is there any way to do that with another program/method?

BTW I have CS3

Likely impossible, becuase it needs to interpolate the existing pixel data to create the bigger image. Now if the image was vector (an image created using mathematical descriptions), you can enlarge it infinitely without losing detail.

iimpossible,since you can't create details out of nothing

Is it impossible to have a 1680 x 1050 screen in both 20' and 22' sizes?

Image size in inches and image size in pixels have nothing to do with each other.

All you need to do is uncheck "Resample Image".

Quote from J.B. :

Is it impossible to have a 1680 x 1050 screen in both 20' and 22' sizes?

Image size in inches and image size in pixels have nothing to do with each other.

All you need to do is uncheck "Resample Image".

Actually they do. The higher resolution in dpi (dots per inch) you have, more pixels you'll need for the same image size in inches/cm. Most common resolutions are 72 dpi for computer graphics and 300 dpi for print (magazines etc.). Try creating 10x10cm image at 72 dpi or 300 dpi, you'll see the difference.

lizard: Unfortunately there is no method for enlarging raster images with good results that i would know. There's a possibility to enlarge image and use smart sharpening, but the results are usually still quite crappy. Maybe you should call the CSI Lab, they can do everything .

I took care to say "size in pixels" not "resolution", so what I stated is true.

In the computer world the term resolution is often used incorrectly to mean amount of pixels instead of pixels per area. This is because there is no real concept of area for computer images unless they are from a scanner. That's why the whole "use 72 dpi for internet" is mostly clueless BS. BTW, if you want to know the dpi value of your screen you can check this out: http://www.raydreams.com/prog/dpi.aspx

For lizard's case the question is what he wants exactly. Print at a larger size but keep the dpi? Or just change the size while keeping the amount of pixels? Both can be done with photoshop.

Quote from J.B. :

Is it impossible to have a 1680 x 1050 screen in both 20' and 22' sizes?

Image size in inches and image size in pixels have nothing to do with each other.

All you need to do is uncheck "Resample Image".

it does.

the difference is just you use dpi (dots per inch) in printing and ppi (pixels per inch) on screens.

but the same theory applies, if you want to blow up an image and try to maintain the same resolution, you will lost detail.

so if you use a 1680 x 1050 screen in both 20' and 22' sizes. the 22's screen will show a lower ppi then the 20', and if that's below the ppi your monitor is capable of showing, you are actually losing some details.

Quote from J.B. :

For lizard's case the question is what he wants exactly. Print at a larger size but keep the dpi? Or just change the size while keeping the amount of pixels? Both can be done with photoshop.

Technically you are correct but that's pointless. what you are saying is just that you can increase the file size while maintain the dpi value, by mulitplying each pixel a number of times.

sure you still can get 300dpi but actually the extra pixels hold NO extra information, it's like doing an animation on two. you have 24fps but actually there's only 12 REAL frames.

in this way the number of dpi means nothing, the extra pixels are just voids and visually it will still be blurry/blockly depending on whether you use resampling.

I am sure lizard means he wants to blow up a picture while maintaining the level of details. And in this regard it's impossible.

Quote from J.B. :

IIn the computer world the term resolution is often used incorrectly to mean amount of pixels instead of pixels per area. This is because there is no real concept of area for computer images unless they are from a scanner. That's why the whole "use 72 dpi for internet" is mostly clueless BS.

Actually you are wrong.

in the old days there's no standard in monitor resolutions, but nowadays the trend is it's going down the route of standardizing, PC will mostly be 72ppi and mac will use 90ppi. Of course not all of the monitor following this standard (some high end ones goes above 200ppi) but as a general guide in digital interface design, it's not clueless BS.

Define "maintain level of detail".

And no you don't lose any detail by replacing a 22' 1680x1050 screen with a 20' 1680x1050. You just get a lower area for the same details.

Also I didn't say anything about multiplying pixels. I said you can either just change the print size, which is a matter of changing a couple of bytes and does not change the file size. Or you can use a resampling algorithm which actually does increase the amount of pixels. Depending on type of image and method used the results can in fact be perceived as having more detail (think upscaling DVD player).

Quote from JJ72 :

Actually you are wrong.

in the old days there's no standard in monitor resolutions, but nowadays the trend is it's going down the route of standardizing, PC will mostly be 72ppi and mac will use 90ppi. Of course not all of the monitor following this standard (some high end ones goes above 200ppi) but as a general guide in digital interface design, it's not clueless BS.

It's completely cluless. dpi is just meta data that you can change with a hex editor. An internet browser doesn't even look at it. And there is no such thing as a dpi standard for monitors. I already linked to a dpi calculator that will tell you the value. Mine has 90 dpi. My laptop, which displays all the images on this page exactly the same, without losing any details, has 85.3 dpi.

First hit in google: http://www.scantips.com/no72dpi.html

it's ppi.

dpi is just used for printing.

there're standard in monitor resolutions. (just no absolute)

That's why graphic cards give you 4 to 5 settings instead of being totally linear like setup values in LFS. those settings are usually base on some standard ppi values like 72, 90 and so.

and base on these numbers. with 72ppi being most common and supported by lower end graphic cards, it's not clueless.

and again, lets get back on what's the point of maintaining the resolution but without adding details (which I think is the TRUE point of the post)

try printing out a 1024x768 image, once at 72DPI and once at 300DPI (with 'resampling image' switched off in photoshop). The actual image size after printing @72DPI will be 36 cm, at 300DPI it will be 8.7 cm

Quote from J.B. :

Define "maintain level of detail".

And no you don't lose any detail by replacing a 22' 1680x1050 screen with a 20' 1680x1050. You just get a lower area for the same details.

Also I didn't say anything about multiplying pixels. I said you can either just change the print size, which is a matter of changing a couple of bytes and does not change the file size. Or you can use a resampling algorithm which actually does increase the amount of pixels. Depending on type of image and method used the results can in fact be perceived as having more detail (think upscaling DVD player).

level of detail as how sharp is image is to human eye.

as I said "if that's below the ppi your monitor is capable of showing, you are actually losing some details. "

of course if that isn't the case, there's no difference.

changing print size alone will decrease the dpi, and hence lost in level of details.

I dunno about DVD player, but of a bitmap image, there's no way you can increase the physical size of an image while maintaining the level of detail/sharpness/whatever you call it.

Quote from J.B. :

First hit in google: http://www.scantips.com/no72dpi.html

I think that's just nitpicking.

so we say no to 72dpi, what would we use?

70? 71? 75? 82? none of these actually works by their definition.

72 is a good base value on most people's monitors, and no major difference will appear if people runs 70 or 80 dpi. so using a value that's standard instead of changing it here and then, what's the problem?

Quote from JJ72 :

it's ppi.

dpi is just used for printing.

there're standard in monitor resolutions. (just no absolute)

That's why graphic cards give you 4 to 5 settings instead of being totally linear like setup values in LFS. those settings are usually base on some standard ppi values like 72, 90 and so.

and base on these numbers. with 72ppi being most common and supported by lower end graphic cards, it's not clueless.

Doesn't make sense to me. ppi is defined by screen, not by GPU.

Quote from JJ72 :

and again, lets get back on what's the point of maintaining the resolution but without adding details (which I think is the TRUE point of the post)

That is the question. I honestly understood lizard as wanting to enlarge print size but being unhappy with artifacts that were introduced by resampling. That's why I said disabling resampling is the answer. You may well be right that he in fact wants to improve the detail of his image in which case he can only try the different resampling methods and see if he likes the result. I think Paint Shop Pro has more algorithms to choose from and there are loads of expensive add-on resamplers for PS.

Lol, this is more chat room than format at the moment.

Quote from JJ72 :

level of detail as how sharp is image is to human eye.

as I said "if that's below the ppi your monitor is capable of showing, you are actually losing some details. "

of course if that isn't the case, there's no difference.

changing print size alone will decrease the dpi, and hence lost in level of details.

I dunno about DVD player, but of a bitmap image, there's no way you can increase the physical size of an image while maintaining the level of detail/sharpness/whatever you call it.

I'm not sure you're getting it. The thing is that a computer doesn't care what the dpi value of an image is. Only a printer cares. Even a monitor doesn't care as it just shows, pixel by pixel, what the monitor tells it to. The dpi value only exists as a couple of bytes in image files, so the monitor never even gets the chance to care.

I'll try with a question. If I send you an image without a dpi value tag, how would you go about trying to find out the 'true' dpi value for that picture? What are you going to measure?

Quote from J.B. :

I'll try with a question. If I send you an image without a dpi value tag, how would you go about trying to find out the 'true' dpi value for that picture? What are you going to measure?

There's no 'true' dpi.

But the amount of pixels would tell me straight away if it will be any good for my A2-size art quality printing needs when I do know my printer's lpi.

And you two - enough with the Wikipedia and Google search dick waving.

And to OP's question - if we talk about ink ending up on paper instead of a screen:

In theory and layman's terms, no, if your image does not contain enough information in the first place you'll lose detail.

In practical terms you have several options depending on what the hell your bitmap image actually represents. You could vector(depending on the complexity and your skills), you could try different interpolation engines that would suit your image better - or in case of digital photographs - you could simply blow it up and pray to God the photographer used a high quality lens, camera and had a good exposure (MP count means nothing) thus giving you more margin of acceptable image loss before one would go blind looking at the destroyed image.

Quote from spankmeyer :

There's no 'true' dpi.

But the amount of pixels would tell me straight away if it will be any good for my A2-size art quality printing needs when I do know my printer's lpi.

Correct answer. Wasn't asking you though.

Thanks for the responses guys

I just strech it until someone sees that its streched

BTW, your avatar looks stretched.

Back to the original question; Photoshop can create pixels out of scratch, it kind of makes two similar pixels out of one. So technically it is possible.