Is 96dpi the ticket now?

[standingstones]

Someone told me that for internet viewing, we should be sizing

images at 96dpi now, because lcd monitors can't view 72dpi images

clearly. Is this true?

[noshir_patel]

It really doesn't matter what dpi you save as for internet viewing. The browsers ignore it. All that matters is number of pixels wide by number of pixels tall. A common screen "resolution" is 1024x768. I usually size my pictures on the internet to 500x400. I do tag them as 72dpi, but occasionally I forget and leave them tagged as 4000dpi (which is what my scanner's native resolution is). Theoretically, this means that the image is 1/8 inch wide (pretty darn small), but guess what... Internet explorer doesn't display it any differently...

[jim schwaiger]

Stop thinking in dpi and think pixels. 800x800 pixels is the most photo.net desires, and most sites assume some minimum monitor size in pixels, 640x480, 800x600, 1024x768, etc.

 

Monitors (LCD and CRT) have widely different and changeable resolutions. I imagine that you could get anywhere from 50 to 150dpi with a big CRT. Many LCDs are in the 120dpi range.

 

72dpi came from the old printing press days and it just so happened that older CRTs could be about the same. Apple still uses 72dpi and MS went with 96dpi, but neither have much to do with the actual screen resolutions available today.

 

So, forget trying to present an actual size image and pick reasonable pixel dimensions based on the fact that most people have 800x600 or better displays.

[gordonr]

Try reading the thread in the archives <a href="http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=000gO7">Do digital cameras have a DPI setting</a> (http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=000gO7)

[standingstones]

Now I'm more confused than ever. I think you are misunderstanding me. I'm concerned with have the smallest file on the web that I can, without having someone be able to download a good printable image for themselves. Physical sizes (ie. inches) will vary, but nowhere near the size of a full screen. I don't personally see the difference between a 72dpi image and a 96dpi image on my screen, but does an lcd monitor? I don't know anyone with an lcd monitor and have not heard this before and I'm not sure if the source that told me is reliable. He told me it must be 96dpi now so that the lcd's can view the images clearly.

[efusco]

We understand you correctly. the point is it doesn't matter. Save the image at 4000dpi if you want. As long as the actual pixels are in the range of 500-750 pixels on the longest side it will be adequate for viewing on the internet but no where good enough quality for someone to steal and make a print from (unless they want a really good quality 1/4" print!

[standingstones]

A 400x600 pixel image will be a much better printable image at 300dpi, as compared to 72dpi. So, the question is..... do lcd monitors require 96dpi to be able to view images clearly?

[peter nelson]

<I>Now I'm more confused than ever. I think you are misunderstanding me.</I><P>

 

Carolyn, we understand you perfectly. <B><U>FORGET DPI!</U></B> Just think in terms of <B>pixels</B>. A 400x600 pixel JPEG will display <U>exactly</U> the same on your screen or someone's web browser regardless of whether the file (e.g., "File Size" in Photoshop) is set to 72 or 150 or 300 DPI. And if I download that file off your website I can reset it to whatever DPI I want anyway if I wanted to print it.<P>

 

On a broader note, I do <U>not</U> understand some photographers' paranoia about people downloading their images and printing them! It's a non-issue because it is impossible to get a decent print out of any web-sized JPEG anyway! Most of the images on my website are around 600x600 pixels, which is larger than most photog's use on their websites. But if you tried to print that, and you set it to 300 DPI you could make a 2x2" print! If you set it to 200 DPI, which is really too low-res for decent printing you could only make a 3"x3" print!

[peter nelson]

<I>A 400x600 pixel image will be a much better printable image at 300dpi, as compared to 72dpi. So, the question is..... do lcd monitors require 96dpi to be able to view images clearly?</I><P>

 

Carolyn, listen to us, please: DPI is like the points on "Whose Line Is It Anyway!": it <U>doesn't matter</U>. Like someone else said, you can make your image 4000 DPI or 11 DPI, it will look exactly the same on the web browser. Pixels . . . just think in terms of pixels. If your lcd display is 1024 x 768 pixels, and you have a 512 x 384 pixel image it will take up exactly 1/4 of your display.

[peter nelson]

<I>A 400x600 pixel image will be a much better printable image at 300dpi, as compared to 72dpi</I><P>

 

No, that doesn't matter. The only thing that matters is the 400x600 pixels. Because one can set it to any DPI one wants. If you have a 400x600 JPEG set to 72 DPI, when I download it I can set it to 300 DPI and it's EXACTLY the same as if you saved it originally as 300 DPI. Exactly the same. Not even the teeniest, tiniest, leastest little bit different. DPI is only used by the printer driver to know how big the print is; it doesn't change the image itself in any way.

[jim schwaiger]

Carolyn, if you upload a 400x600 image and someone prints it from their browser, it will be quite large, but low quality. If they bring it into an image editor and change the dpi to 200 dpi (marginal quality) they will get a 2x3 inch print. Even at 800x800, they really can't get a decent sized, good print. <br><br>

 

If you are scanning a 4x6 print, that means a scanning resolution around 100ppi (for 600x400). If you are scanning film, use about 400ppi. Many people scan at the highest optical resolution their scanner has and then downsample to the appropriate pixel size. That will work too, but can be overkill, especially for web use. A lot of scanners can go about 10 times what's needed for web usage which makes the original files 100 times larger than they need to be.<br><br>

 

Please check out <a href ="http://www.scantips.com" > www.scantips.com</a> for scanning and printing tips.

[angel_o.]

Carolyn, <br><br>

as everybody else said: <I>dpi</I> doesn't matter on a monitor.<br><br>

 

DPI means "dots per inch", if you take a closer look your monitor (doesn't matter CRT, LCD or whatever) has a physical size, e.g. my 19" monitor has a viewable area of aprox. 14.2 inch x 10.8 inch. At a resolution of 1280x1024 pixels. Thus, the <i>dpi</i>s of my monitor are calculated as follows:<br><br>

- <i>horizontal-dpi</i>=1280 pixels/ 14.2 inch = aprox. 90 pixels/inch <br>

- <i>vertical-dpi</i>=1024 pixels/10.8 inch= aprox. 95 pixels/inch<br><br>

If I change the resolution to 1800x1440 pixels the dpi's change to:<br><br>

- <i>horizontal-dpi</i>=1800 pixels/ 14.2 inch = aprox. 127 pixels/inch<br>

- <i>vertical-dpi</i>=1440 pixels/10.8 inch= aprox. 133 pixels/inch<br><br>

But still, it's the same monitor, isn't it?<br><br>

In the earlier days, what we call today <i>pixels</i> was called <i>dots</i>, other word for the same meaning. I guess your monitor is wider than 1 inch and your images are wider than 72 pixels, so therefore, the statement <i>"we should be sizing images at 96dpi now, because lcd monitors can't view 72dpi images clearly"</I> is BS.

[andy_piper2]

Carolyn: Most browsers automatically size pictures they read off the web to the native resolution of the monitor in use at a 1-to-1 pixel ratio.

 

Whatever total number of pixels you give us, our browsers and video cards will just resize the gross external dimensions of the image as needed in order to 'map' every one of your pixels to a pixel on the screen (i.e. no loss of detail). As someone mentioned - you can even post an image at 600ppi and a half-inch wide - and the software/hardware will just enlarge it on-screen until the pixels match.

 

A picture 144 pixels by 216 pixels will be 2" by 3" on my Mac, which is still a 72ppi system (if I stick a ruler up to the screen), while it will just look smaller (1.5" by 2.25") - but otherwise identical - on a 96ppi Windows monitor. Regardless of whether your saved it as a 2"x3" or a 1.5"x2.25" originally.

 

If there is a 'change' recommended from 72 to 96 for internet use, it mostly just reflects the fact that 96ppi is becoming more commonly used, and thus helps you know exactly how large the image will appear on screen for the majority of viewers.

[timothy_swan]

The easy answer is that your friend is incorrect. There is no degradation of images on an LCD monitor if you save at 72 dpi. I'm a professional web designer and I work with 72 ppi images all day long.

[standingstones]

Thank you very much! That's what I needed to know!

[jakob_norstedt_moberg]

Carolyn, I'm sorry that you need an easy answer to be satisfied. Please, try to understand that your life will become much easier to live if you spend some time trying to understand all the postings of this thread.

 

Timothy, as many others already have said, the web does not care about dpi, it is only the number of pixels that counts.

 

I realised long ago that there is a huge canyon between those more technically oriented and those working at, for example, small local newspapers. I am fully understanding how dpi and pixels works, but still I am very careful to save the picture at the right dpi before submitting it to a local Swedish newspaper.

 

My experience is that if you scan your negative at 2400dpi and leave it set at 2400dpi when you submit it to a paper you should not be surprised if they mail you back and tell you that your picture was only 36mm wide and too small to be useable. They do not care about it being 2600x2400 pixels or more. So I have adopted, and always put it to 170dpi to be on the safe side, because that is what they want for their newspaper and I do not want my picture to be delayed.

[ptucci]

For some reason, Photopaint defaults to -1130 DPI on scans. If I forget to change this, the images still show and print fine. Now if I could just find my college math book with imaginary numbers!

[peter nelson]

<I>I realised long ago that there is a huge canyon between those more technically oriented and those working at, for example, small local newspapers. I am fully understanding how dpi and pixels works, but still I am very careful to save the picture at the right dpi before submitting it to a local Swedish newspaper. </I><P>

 

You got that right! And it's not just newspapers. A year ago I submitted some files to be printed at a local semi-pro commercial lab (i.e., not a Ritz or mall minilab). They were still set to the resolution I had scanned them at - 2800 DPI or somesuch. I said I wanted 8x12's and they said they couldn't do it because at the file's resolution they could only make 1x1.5 inches. And this was the lab OWNER I was talking with.<P>

 

None of this stuff is rocket science. It barely qualifies as algebra - it's really simple arithmetic. I don't understand how the lab and newspaper workers we're talking about ever figure out their cars' gas mileage when they fill up their tanks, or adjust a recipe in a cookbook for some number of servings other than what it said in the book.

[steve_hovland]

I size my web images 4" by 4" at 100 ppi = 400 x 400 pixels.

[gooseberry]

Carolyn,

 

What some folks eluded to, but, unless I've overlooked it, none has explicitly spelled it out, here is how it works. Let me demonstrate it on an example: Consider what would be the difference between the same picture saved first at 100dpi as a 4"x6" image and then at 50dpi as a 8"x12" image if you post the two files on the web?

 

The answer is *NONE* whatsoever! Why? Here's were the elementary algebra comes in: if you multiply resolution by size (in one dimension, either width or length), the result would be exactly the same -- this is what every monitor will see.

 

Let's check it:

 

100dpi * 4" = 400 pixels, which is no different from 50dpi * 8" = 400 pixels

 

Same goes for the longer side:

 

100dpi * 6" = 50dpi * 12" = 600 pixels

 

Easy? Just to reiterate: Because the size of the image was adjusted accordingly (from 4"x6" to 8"x12"), the change in resolution it was saved at (100dpi vs. 50dpi) was effectively 'neutralised', and the two files will be display identically, i.e., they will occupy the same area on a given screen (exactly 400x600 pixels) and will exhibit no difference in quality.

 

Hope that helps.

[sk_arts]

DPI is a measurement of pixel density not display size. Images on the internet will always be displayed at 1:1, regardless if they are at 2 dpi or 20,000 dpi. If the image is 100x100 pixels, it will be displayed at 100x100 pixels, and the size of the pixels, and thus their density depend on the resolution of the monitor. If say a monitor was 100x100, then the image would fill the entire screen. But if it was 1500x1500 it would fill only 15% of the screen.

 

If that 100x100 screen was 20" wide then the pixels themselves would be 0.2x0.2" and very visible. If the screen was 1" wide the pixels would be 0.01" and far less visible. (i think thi is right, but in any case, smaller screen with same number of pixels=smaller, denser pixels)

 

Ofcourse, square screens don't exist as far as I know.

 

DPI refers to how the image is distributed on OUTPUT, as in, on a printer or image setter, as the paper and film don't have a resolution to speak of, and the data in the image is used to create the screen on a print.

 

I doubt that internet applications are even capable of registering information about DPI, and they likely ignore it entirely as a part of optimizing speed.