[Jewelltrail]

I like using the Fast Stone software to process my Raws because I get good results and it is quick compared with Lightroom. However, the Fast Stone only processes Raws into 72dpi. There is no support for dpi in Fast Stone from what I can see.

I have to import the JPG I processed in Fast Stone into Lightroom and increase the DPI there. There must be a better way? Is there another version of FS which allows DPI adjustments? Any ideas?

[rburgoss]

DPI means nothing if you don't count the total pixels (length & height). Almost all pictures from digital camera come out at 72 dpi, but the difference is the total pixel count.

It is not the same to have a 1 megapix picture than a 6 meapix picture, even if both are at 72 dpi.

With pentax DSLR's, 6 megapix pics measure 3008 x 2008 pixels, always at 72 dpi. That means the picture will measure around 41.77 x 27.88 inches. That is pretty big don't you think so?

If you resize the picture to 150 dpi without resampling (keeping image file size), then the picture will measure 20 x 13.4 inches. Still a big enlargement.

Hope this helps you understanding that dpi means nothing if you don't have the total pixel count.

RB

[Jewelltrail]

rburgoss DPI means nothing if you don't count the total pixels (length & height). Almost all pictures from digital camera come out at 72 dpi, but the difference is the total pixel count.

Thanks for trying to help me, but I am still very unclear about what you are trying to highlight for me. I have read that before you print, select the print size, then use the correct DPI. I have read that smaller pics need more DPI, because they are viewed at a closer range.

So, I am looking to process my Raws so that I can print them at any size I desire. But now I am very unclear. Can you help me some more?

How do I calculate the total piel size? I am shooting with a K20d. Thanks.

[Nesster]

Most print drivers and photo editing programs will do this for you. They re-DPI the bitmap to fit your paper size... and usually warn you if the DPI comes out below some number.

The way I do: I use ps Elements, say, and first crop etc to accommodate the paper aspect ratio. (Unless of course I don't) Then I print from the edit program, adjusting the parameters based on what size I'm printing... if the bitmap at, say 250 DPI, is too small, I'll likely go and do a bicubic resize and re-sharpen specifically for the large size print. If I'm printing smaller, I usually just let the edit program / print driver handle the situation.

Using the photoshop resize thing is very educational. I think other programs have similar.

Try changing the DPI without resizing / resampling: you'll see the bitmap stays the same size but the 'printed' size changes. This gives you an idea of the DPI your bitmap supports at a given 'print' size.

[Jewelltrail]

Nesster and rburgoss--Thank you!

[rburgoss]

As Nester said, most image processing software will simply "resize" your image to adjust to your printer, and some will warn if dpi's are too low for the selected size. But if you want to go deeper into the dpi subject, the following may be a good reference point:

It all boils down to actual printing resolution for a given print size.

I work in graphic arts and have stated some basic rules for printing (lab or home printing with a good photo printer).

Remember that the bigger the print is, the "farther" you'll look at it. For example, a 4x6 print is usually looked at 10 to 20 inches away, but a 24 x 36 inch poster, will be looked at several feet away.

That means that actual printing resolution, will "increase" as the print size "reduces".

According to some eye doctor sources, the human eye without the help of magnifying devices, is capable of resolving up to 200 dots per inch (dpi), at 20 cms (about 8 inches) away. That is for a 10 year old kid with perfect vision.

Human eye resolving power diminishes with age, being at around 160 dpi at age 25 and as low as 125 dpi at age 40.

Based on that, you can crop and resize your photo files for printing purposes, according to the following basic table. Remember, resolution given is at actual print size.

For 4x6 use a 200 dpi resolution. That is, a file with at least 800 x 1200 pixels.

For 5x7, use a 170 dpi, file size at least 850 x 1190 pixels

For 8 x 10, use a 150 dpi, file size at least 1200 x 1500 pixels.

For 11 x 14, use about the same as 8 x 10.

For 12 x 18, use 130 dpi, file size 1560 x 2340 pixels

For 17 x 22, use 120 dpi, file size 2040 x 2640 pixels.

Remember, those resolutions are AT LEAST, meaning that anything below will be apparent in lack of resolution. Anything above is just waisting hard drive (cd, dvd, etc) space. As for me, I always shoot in highest resolution given by the camera, then crop and resize as needed and save the file with a different file name and keep the original file "untouched". I can't remember how may times I've had a nice 5 x 7 print, and some time later, wanted a 12 x 18 or bigger print.

Of course, this is my personal experience. Anyone can have different experiences.

Anyway, now in the gigabyte era, file size is becoming less of a concern (when big files are used). It all depends on your hard drive space and your back up methods.

Hope this helps.

Robert B

As Nester said, most image processing software will simply "resize" your image to adjust to your printer, and some will warn if dpi's are too low for the selected size. But if you want to go deeper into the dpi subject, the following may be a good reference point:

It all boils down to actual printing resolution for a given print size.

I work in graphic arts and have stated some basic rules for printing (lab or home printing with a good photo printer).

Remember that the bigger the print is, the "farther" you'll look at it. For example, a 4x6 print is usually looked at 10 to 20 inches away, but a 24 x 36 inch poster, will be looked at several feet away.

That means that actual printing resolution, will "increase" as the print size "reduces".

According to some eye doctor sources, the human eye without the help of magnifying devices, is capable of resolving up to 200 dots per inch (dpi), at 20 cms (about 8 inches) away. That is for a 10 year old kid with perfect vision.

Human eye resolving power diminishes with age, being at around 160 dpi at age 25 and as low as 125 dpi at age 40.

Based on that, you can crop and resize your photo files for printing purposes, according to the following basic table. Remember, resolution given is at actual print size.

For 4x6 use a 200 dpi resolution. That is, a file with at least 800 x 1200 pixels.

For 5x7, use a 170 dpi, file size at least 850 x 1190 pixels

For 8 x 10, use a 150 dpi, file size at least 1200 x 1500 pixels.

For 11 x 14, use about the same as 8 x 10.

For 12 x 18, use 130 dpi, file size 1560 x 2340 pixels

For 17 x 22, use 120 dpi, file size 2040 x 2640 pixels.

Remember, those resolutions are AT LEAST, meaning that anything below will be apparent in lack of resolution. Anything above is just waisting hard drive (cd, dvd, etc) space. As for me, I always shoot in highest resolution given by the camera, then crop and resize as needed and save the file with a different file name and keep the original file "untouched". I can't remember how may times I've had a nice 5 x 7 print, and some time later, wanted a 12 x 18 or bigger print.

Of course, this is my personal experience. Anyone can have different experiences.

Anyway, now in the gigabyte era, file size is becoming less of a concern (when big files are used). It all depends on your hard drive space and your back up methods.

Hope this helps.

Robert B

WHAT?

If your just looking at it on the monitor than 72 dpi is fine resize the pixel size so it fits on screen. Now if your going to print it out that's a different story. Forget about the pixels. That's screen size. DPI and the document size is what matters. 300 dpi at the final size and crop. Bring you raw files into LR or photoshop at about the size you want. Remember you can alway downsample but you don't want to upsample. These programs will add pixels to get the dpi but it's never as good as bringing it in at the right quality to start. Any more is wasted resolution. Of course if you're creating a file that's going to be a billboard then all you need is 72 dpi. You are correct to an extent about viewing distance. But with glasses I can tell 300 vs 100 dpi at about 2 feet.
It also depends on the printer you're going to also. If you're just gong to a cheap inkjet than a little less resolutin is ok. It'lll bleed enough to round over the dots. The high end equipment won't however and require a higher res. file. Talk to whoever is going to output it and ask what their requirements are for their equipment. When I talk to my clientele I first determine which equipment it's going to and then make the decision as to what we can get away with.
And I too am a graphic designer and have worked in printing/professional photography for over 30 years. From presswork to bindery to QC and have even done dot etching on film. I will admit that most of the time however I am looking at photos at about 3 inches through a loupe.

This has been discussed in quite a few other threads too. Just look back at some of those for even more opinions.

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Last edited by graphicgr8s; 09-26-2008 at 08:11 AM.

[Jewelltrail]

graphiccgr8s:"If your just looking at it on the monitor than 72 dpi is fine resize the pixel size so it fits on screen. Now if your going to print it out that's a different story. Forget about the pixels. That's screen size. DPI and the document size is what matters. 300 dpi at the final size and crop. Bring you raw files into LR or photoshop at about the size you want. Remember you can alway downsample but you don't want to upsample. These programs will add pixels to get the dpi but it's never as good as bringing it in at the right quality to start. Any more is wasted resolution. Of course if you're creating a file that's going to be a billboard then all you need is 72 dpi. You are correct to an extent about viewing distance. But with glasses I can tell 300 vs 100 dpi at about 2 feet.
It also depends on the printer you're going to also. If you're just gong to a cheap inkjet than a little less resolutin is ok. It'lll bleed enough to round over the dots. The high end equipment won't however and require a higher res. file. Talk to whoever is going to output it and ask what their requirements are for their equipment. When I talk to my clientele I first determine which equipment it's going to and then make the decision as to what we can get away with.
And I too am a graphic designer and have worked in printing/professional photography for over 30 years. From presswork to bindery to QC and have even done dot etching on film. I will admit that most of the time however I am looking at photos at about 3 inches through a loupe.

This has been discussed in quite a few other threads too. Just ook back at some of those for even more opinions."

This discussion seems more in line with what I was researching--thank you very much. I wish these things were not so complicated, but clearly they are because opinions seem to differ widely.

Thank you very much!

[procyon]

I like using the Fast Stone software to process my Raws because I get good results and it is quick compared with Lightroom. However, the Fast Stone only processes Raws into 72dpi. There is no support for dpi in Fast Stone from what I can see.

I have to import the JPG I processed in Fast Stone into Lightroom and increase the DPI there. There must be a better way? Is there another version of FS which allows DPI adjustments? Any ideas?

There have been countless DPI threads here recently, but to simplify things a lot:

1. Your camera produces a file that has some fixed number of pixels.
2. Your camera knows nothing about DPI because it doesn't know what size you want to print your image ( remember - DPI is dots per inch, so to calculate it you have to divide the number of pixels on one axis with the length of paper in inches)
3. Now look at the image file your RAW converter produced - how many pixels does it have ? If you multiply the length and width in pixels do you get approximately the number of megapixels your camera has ? (for example if the image is 2000 x 3000 pixels you get 6 million pixels or 6MP)
4. If it is the same size as your cameras advertised megapixels (+- a few percent) then you are getting all the data the camera has recorded !. It doesn't matter then if it has DPI 1 or DPI 72 or DPI 300 or DPI 10000.
If someone can give me an example of why a let's say 2000x3000 pixels image file(remember we are talking about a file here, not a printout ! ) at 300DPI is better than a 2000 x 3000 pixels image file at 10 DPI then please, humour me
DPI does not exist before you print your file !
If some software says your RAW converter produced a file that has 72 DPI then your RAW converter just writes this number in the output file (most likely just to write something - as it really has no idea how large you are going to print it.
It's really all about pixels, honestly, pixels are the only thing your digital camera can produce.

There have been countless DPI threads here recently, but to simplify things a lot:

1. Your camera produces a file that has some fixed number of pixels.
2. Your camera knows nothing about DPI because it doesn't know what size you want to print your image ( remember - DPI is dots per image, so to calculate it you have to divide the number of pixels on one axis with the length of paper in inches)
3. Now look at the image file your RAW converter produced - how many pixels does it have ? If you multiply the length and width in pixels do you get approximately the number of megapixels your camera has ? (for example if the image is 2000 x 3000 pixels you get 6 million pixels or 6MP)
4. If it is the same size as your cameras advertised megapixels (+- a few percent) then you are getting all the data the camera has recorded !. It doesn't matter then if it has DPI 1 or DPI 72 or DPI 300 or DPI 10000.
If someone can give me an example of why a let's say 2000x3000 pixels image file(remember we are talking about a file here, not a printout ! ) at 300DPI is better than a 2000 x 3000 pixels image file at 10 DPI then please, humour me
DPI does not exist before you print your file !
If some software says your RAW converter produced a file that has 72 DPI then your RAW converter just writes this number in the output file (most likely just to write something - as it really has no idea how large you are going to print it.
It's really all about pixels, honestly, pixels are the only thing your digital camera can produce.

DPI is NOT Dots per image it's Dots Per Inch. And relates to printouts. Pixels relates to screen size. And you're correct. It has nothing to do with screen resolution. BUT it has everything to do with hard copy output. Try printing something out at 72 dpi. It's all bitmapped/rasterized. There's just not enough information to get a quality image. And you can't just upsample it in software. It can only guess at where to add the pixels. Imagine trying to make 5 gallons of tea with one tea bag.
Now, it would sound like well, if 300 is good then 1200 is even better. Right? Well no. Printers still have a limit on resolution and anything over 300 at final print size is just wasted space/time, etc.
Now, on the screen you pretty much can't tell the difference between 300 and 100 at the same size but you sure can in print.
Start out with the highest quality your camera can give you, then crop, then downsample, then print. You can always go down, but not up.
And you're right. In Photoshop it's not listed as DPI it's PPI (or pixels per inch). But when it comes down to printing the image you still want it at 300 DPI/PPI
And yes, on screen you can tell a lo res file from a hi res.

[procyon]

DPI is NOT Dots per image it's Dots Per Inch. And relates to printouts. Pixels relates to screen size. And you're correct. It has nothing to do with screen resolution. BUT it has everything to do with hard copy output. Try printing something out at 72 dpi. It's all bitmapped/rasterized. There's just not enough information to get a quality image. And you can't just upsample it in software. It can only guess at where to add the pixels. Imagine trying to make 5 gallons of tea with one tea bag.
Now, it would sound like well, if 300 is good then 1200 is even better. Right? Well no. Printers still have a limit on resolution and anything over 300 at final print size is just wasted space/time, etc.

My mistake, it's certainly dots per inch not image. Corrected now.
But the question in this thread is not about printing at 72 DPI. As I wrote earlier I was talking about DPI in file, not DPI used while printing. Lots of software and also cameras write 72 as DPI by default. For example all JPEG files produced by K10D have 72 DPI written in them although there is no restriction in printing them out with much larger DPI. This DPI embedded in files causes a lot of confusion, as people assume there is no way to print them out at larger DPI without resampling.
That is of course false, as this DPI has only informative value, it does not change image data. In fact I know several programs that allow to set this DPI value in JPEG files to arbitrary values, without changing any image data. What the thread starter is doing is just that - using a program to change the DPI to some other value to get better output - but this is completely unnecessary.
So I'm absolutely not talking about the DPI that is used to print the image.
I just suspect that the thread starter is a victim of a program writing 72 DPI to output files even though they are full resolution. I seriously doubt that FastStone would only output images that are thumbnail sized.
I just don't see why a JPEG file exported from RAW converter X that has 72 DPI written inside would be any worse than the same image with 300 DPI written inside. If those images have the same amount of identical pixels then they are equal in every respect.

Here are two files. One of them is 10 PPI. The other higher. Can you tell them apart? It's the same image just downsampled.
PPI/DPI and image size are totally interconnected.
Hmm. Guess I am wrong they look identical.

I like using the Fast Stone software to process my Raws because I get good results and it is quick compared with Lightroom. However, the Fast Stone only processes Raws into 72dpi. There is no support for dpi in Fast Stone from what I can see.

I have to import the JPG I processed in Fast Stone into Lightroom and increase the DPI there. There must be a better way? Is there another version of FS which allows DPI adjustments? Any ideas?

Question. At 72 PPI what are the dimensions of the picture?

One other thing to consider here is if you are saving it back as a jpeg. Everytime you save it it is losing quality. JPEG's are very "lossy" when resaving because of the compression. On the otherhand tif files are not and can be saved back on themselves without quality loss

[procyon]

Here are two files. One of them is 10 PPI. The other higher. Can you tell them apart? It's the same image just downsampled.
PPI/DPI and image size are totally interconnected.
Hmm. Guess I am wrong they look identical.

I can see that you are using a K10D.
Please choose any of your pictures and look at its information with any program that shows EXIF data. Do this with an unprocessed straight out of camera JPEG not touched with any image editing program. Look what its DPI is. Yep ... its 72 DPI. So the thread starter got exactly what the camera would have given when shooting JPEGs. Does that mean that we (I also have K10D) always have to resample if we want to print at 300DPI ? I'd say no, because that value inside the files EXIF info is totally arbitrary and meaningless. My girlfriends powershot has 180 DPI written there .... wow, is it better in some way because of that ?
Please remember - we are talking about DPI information written in files by image editing programs, not the DPI values you choose when you print or resample.
A K10D image printed at 72 DPI would be totally huge. The thing is - before you know what the printed image dimensions in inches/centimeters/whatever unit of physical length are you can't tell what the DPI will be. DPI equals pixels divided by length. If length is not known you just can't do the division.

And I apologize for not using PPI, I know that it is much more correct to call it that way.

I can see that you are using a K10D.
Please choose any of your pictures and look at its information with any program that shows EXIF data. Do this with an unprocessed straight out of camera JPEG not touched with any image editing program. Look what its DPI is. Yep ... its 72 DPI. So the thread starter got exactly what the camera would have given when shooting JPEGs. Does that mean that we (I also have K10D) always have to resample if we want to print at 300DPI ? I'd say no, because that value inside the files EXIF info is totally arbitrary and meaningless. My girlfriends powershot has 180 DPI written there .... wow, is it better in some way because of that ?
Please remember - we are talking about DPI information written in files by image editing programs, not the DPI values you choose when you print or resample.
A K10D image printed at 72 DPI would be totally huge. The thing is - before you know what the printed image dimensions in inches/centimeters/whatever unit of physical length are you can't tell what the DPI will be. DPI equals pixels divided by length. If length is not known you just can't do the division.

And I apologize for not using PPI, I know that it is much more correct to call it that way.

If you tell me that a file has 72 ppi I can tell you with certainty that at the length and width that that 72 ppi pertains to when printed at 100% it will look like crap.
If you increase the ppi then the actual printed size will decrease if no resampling is done.
The dots that print at 300dpi (yes that is correct in this usage) are smaller. 300 dots lined up in a row one inch long. When you print something at 72 dpi then the dots are larger and more noticable.

One question though. How do you know I used the K10D? From my signature?