How to shoot at 300dpi ??

[mongo]

Mongo has a project where he has to shoot in RAW and get files in 300dpi. Looking at random at some of his old images there seems to be no sense to it - some are 240 dpi and some 300dpi. Mongo cannot remember how to get one or the other deliberately. Has to be minimum 27cm X 24cm and 300dpi resolution . Using a D800 :-


1. what should the camera be set to ?

2. if Mongo has some large existing files but at 240dpi, what is the best way (Mongo has tried a few ways already) in Photoshop to make them 300dpi which least affects the IQ ?

Any and all advice very gratefully received. There may even be the remnants of a thoroughly chewed aardvark carcass in it for you.......hmmm....

regards

Mongo

[ricktas]

DPI is a printing term for Dots Per Inch. The higher the DPI the higher quality print result a printer can produce. DPI is a term used to denote the quality of a printer, and its ability to produce a high quality print. Basically it is the number of single dots of ink colour that a printer can fit into an inch. DPI is only used as a printing term, and that is it.

PPI is pixels per inch and this relates to the resolution of your photo. If you had 10 pixels per inch, your photo would be very pixelated and 'blocky', so the higher the PPI the better. A 10 PPI photo will still print at 300 DPI on a printer that can print at 300 DPI, it would just be that most of those 300 dots of ink would be blocks of solid colour.

To change your photo's PPI, in PS go to the Image Size menu (Image > Image Size)
Change the Document Size to Inches and set the two (width and height) as required and then set the resolution to 300 pixels/inch.

Just remember that DPI and PPi are different things.

Suppose you have a 100 x 100 pixel image, it could be printed at many different sizes. If you set the image to print at 10 PPI, then you’d have a 10″ x 10″ image. If you set the image to print at 100 PPI, you’d have a 1″ x 1″ image. Note that adjusting this value doesn’t effect the number of pixels in the image at all, it just changes how big the print will be.

[mongo]

Big Big thanks for the explanation Rick. Mongo was familiar to a large extent with DPI but not at all with PPI. So, thanks again.

Where do you want the aardvark leftovers sent to ?

[Eberbachl]

Great explanation from Rick there! I'm not sure if you can maniplulate how they come out of the camera. Out of my K-5 and K-r they are 300 PPI, and looking back on a few old shots it seems my old Nikons did the same. As Rick stated it's easy enough to manipulate that later in PP when scaling the image.

[ricktas]

Nikon offers resolution as an in camera option (well it does on my D3), but this, like many other settings, only applies if you shoot jpg.

[ameerat42]

1. what should the camera be set to ?

2. if Mongo has some large existing files but at 240dpi, what is the best way (Mongo has tried a few ways already) in Photoshop to make them 300dpi which least affects the IQ ?

Any and all advice very gratefully received. There may even be the remnants of a thoroughly chewed aardvark carcass in it for you...


Re:
Q1. Good Q. (No good answer.)
Q2. Mongo had better be sure to NOT tick "Resample Image" box. That way he will not affect the IQ of the original image.

Don't think I did this just for the that reward:D
Am.

[JM Tran]

Any camera will be able to select the MP and resolution, but I have never seen a camera - from compacts to medium formats - be able to select the exact PPI/DPI - thats all done in the processing.

[Warbler]

Mongo, when you view your RAW file in ACR, there is a line right at the bottom (in the middle) that if you click on it, you can choose options for how the image comes across into photoshop. It's called workflow options. You can up-res it. You can set the DPI. You can choose the colourspace. You can set your bit-depth. Once done, it should remember that for your camera. Once you look at the file size in photoshop after that, it will show the resolution you chose. It keeps that info in the XMP file too.

Give it a try. Err, no need to send me any Aardvark. I've already got some. ;)

[Ms Monny]

I too have seen this, Mongo, when in Elements but it is PPI not DPI. Mine is 240 PPI. I think that when you print, you set the DPI....well, thats what I've always done.

Warbler, Can you only do this in ACR (which I don't use) or LR? I can't find anything like you described when in LR.

[Warbler]

Warbler, Can you only do this in ACR (which I don't use) or LR? I can't find anything like you described when in LR.

Sorry Ms M. I don't use Lightroom, So I have no clue about it. Given that Lightroom is just ACR on steroids with a built in DAM module, I'm guessing it will be there somewhere.

It's in the middle down there under the file name. You'll see it underlined.

92861

[Kym]

DPI only has meaning when outputting.
A pixel is a pixel.
How it displays or prints depends on the monitor or printer.

Think about this... if I have an image 100px x 100px it will display on my screen (assuming no sizing) using 10,000 pixels (100 x 100).
If my monitor is 100 px / inch then it will display 1" sqaure.

If I print that image on a 300dpi printer (no scaling) it will be about 1/3" square.

[Warbler]

Kym is of course correct. As photographers we all know that. Dealing with folks who have no idea is when the difficulty arises about resolution or DPI. Wait till someone asks for an image for magazine advertisement and tells you it must be 2MB. :Doh:

Explaining that pixel dimensions and DPI are the only factors affecting print size and quality won't get you far. I have however found that by setting my workflow to 300dpi via the method I mentioned means I have a "set and forget" that works well for me.

[Kym]

Part of the problem is that JPEG is a compressed format so saying 2Mb is in a crude way trying to define a quality level.
It is the wrong way to do it - but ignorance is a powerful force :D

[arthurking83]

Kym is of course correct. As photographers we all know that. Dealing with folks who have no idea is when the difficulty arises about resolution or DPI. Wait till someone asks for an image for magazine advertisement and tells you it must be 2MB. :Doh:

it's because the person asking(for the images) has no clue .. or is just plain dumb @$$ lazy.


.... Explaining that pixel dimensions and DPI are the only factors affecting print size and quality won't get you far.

ok, now we've established that they have no clue! :p


.... I have however found that by setting my workflow to 300dpi via the method I mentioned means I have a "set and forget" that works well for me.

you're just making it easy for the clueless magazine person to print the image. :D

[Mark L]

For those with Canon, and therefore no "thoroughly chewed aardvark carcass" for me.
Take photo in Raw (oops, just check, will do it with any file format). Select photo in Canons DPP , select convert and save. A little box allows you to set DPI.

92867

[Ms Monny]

Kym is of course correct. As photographers we all know that. Dealing with folks who have no idea is when the difficulty arises about resolution or DPI. Wait till someone asks for an image for magazine advertisement and tells you it must be 2MB. :Doh:

Saw this just now on the net.....

http://farm9.staticflickr.com/8451/7936341576_5a6f4ee0b1.jpg (http://www.flickr.com/photos/missmonny/7936341576/)
megapixels (http://www.flickr.com/photos/missmonny/7936341576/) by Miss Monny (http://www.flickr.com/people/missmonny/), on Flickr

Is that what you mean MB or is megapixel different? ( sorry for my naivety! :o )

[arthurking83]

I just tried that "Megapixels" setting in LR4, and it's not really useful in some ways, although I can see how it could be useful, if a specific Megapixel value is required.

I suppose you have to have a very good understanding of Mp, pixel dimensions, crop ratios and be a master mathematician at the same time!

I saved a previously 4288x2412 pixel image cropped to a 16:9 pano format using the same values as above(2.0Mp and 72ppi), and it 'randomly' chose the resultant file size in the saved image to be 1885x1060 and 1.44Mb.
(I had no input in that at all) 1885x1060 equates to 2 megapixels

Then I saved one at 300ppi and the resultant file had exactly the same file values as above with the 72ppi export routine!

So the Megapixel export routine is literally that! .... saves the file to the number of pixels specified in the dialogue box.

Note tho that strictly speaking the output from Lr on this is to the word, but it seems to be a bit silly exporting to a dimension such as 1885x1060, which is quite close to a standard format resolution tha tis HD(1920x1080).
1920x1080 is also considered to be a 2.0Mp image too!(just not literally .. it's really 2.07Mp, but the 0.07 component is rounded to a number that makes more sense to humans.

So as they(Adobe) say, it may be useful to a degree but that degree is too literal and doesn't take into account a standard format that is commonly used(such as above the common HD format of 1920x1080).

[mongo]

Mongo thanks you all very much. He has tried Warbler's method and it is spot on for what Mongo wants to do. Indeed, Mongo is going to leave his ACR at 240 for nearly all his stuff but only change it to 300 when preparing these select images for magazine printing.

Again, thanks to all. You have been a great help. Sadly, no one seems to want the aardvark leftovers. That probably means more for Mongo who is going to go and bury them for retrieval and use another time.

[ricktas]

When you start using MP as the only sizing target, you could find that you end up more confused than ever. 2MP sounds ok, but for example, if your camera takes photos that are 4,256 x 2,832 as an example, then this is 12,052,992 or 12mp.

Now, even further off-topic, if I may... The marketing guru's also cause an abomination of the term pixels as well. How often do we see new camera's advertised with the back LCD being 920K? Makes us think our LCD is capable of showing 921,000pixels right? Well sort of, read on...

Take the Canon 50D LCD screen that is quoted by Canon as being a 920K screen. Sounds impressive right? 920K is 920,000. But each dot can only be red, green or blue, and the marketing guru's decided to use that to their advantage and count each pixel site for each colour, separately. So really your screen is 920,000/3 or 307,200 pixels, as each one can only be one colour at any one time. Now guess what 307,200 is really 640x480. Most smart phone screens are higher resolution. Yep, that 920,000 pixel LCD screen is just 640x480. The Marketing guru's have made you believe your LCD screen is some phenomenal quality, when it's not..really.

Is it any wonder people get confused over PPI and DPI when this sort of thing is presented to us?

[Ms Monny]

wow....cheeky buggers!! :eek: