Dropbox File Size

[rpcrowe]

I realize that emailed images are reduced to 72 ppi (or thereabouts) despite whatever the native size of the image might be. I think that I am correct in this assumption.

We share text files across our Maltese Rescue California membership using Dropbox. If I place a 240 ppi JPEG file in my Dropbox, will it be 240 ppi when the member opens it. There are some files that we need printed at various locations and I want to ensure that the resultant prints are up to standards and not printed from a small emailed file.

If Dropbox won't do it, how can I send larger sized files via the Internet?

Thanks in advance for your help...

[Loose Canon]

As far as I know Richard when I place a ‘jpg file in a dropbox the people who share it get it at whatever resolution I put it in there with.

I know if I re-open it after placing it in Dropbox it is all the same as when I put it in there.

[Mike Buckley]

Perhaps your email client changes the file characteristics but mine doesn't.

Dropbox doesn't change anything about the file itself.

However, I think you're confusing DPI and PPI as they pertain to printing. That's easy to do.

[Loose Canon]

Come to think of it, my emails do not resize as a matter of course either.

[Colin Southern]

Hi Richard,

It's really easy - and there are a number of ways to do it.

Personally, I just use Google Drive - I think the maximum file size is browser limited at 2GB. If it helps, just email them to me individually, and I can host them for you for a while (max via eMail is 25MB each).

Dropbox is another very popular service, although I've only had a little to do with it.

When eMailing photos it's usually selectable as to whether the system reduces their size or not -- if in doubt, just ZIP them first.

[rpcrowe]

Thanks for the input... And, Colin, thanks very much for the offer! I am going to try Dropbox since that is what the rest of the folks in the organization are using for their file transfers.

It makes it easy since we can have an individual file for each dog which can be kept up-to-date by the persons responsible for the dog (usually the foster family) but, have that file with information like intake sheets, medical and vaccination reports and adoption forms available to any organization member to draw from. That way, when a dog is adopted, we can just print out the PDF file with all pertinent informationand give it to the adopting family...

[Colin Southern]

No worries Richard.

Both Drop Box and Google Drive have 2 "modes" of operation (for want of a better word). With the first you can just upload files manually and then share the download links (which is what you're after) whereas with the 2nd, you download software to your PC and it'll keep a bunch of files synchronised.

So long as you set your permissions correctly you should be fine.

[Black Pearl]

Can you explain what you think "reduce to 72 ppi" will do to a file?

If you simply change the ppi of a file nothing actually happens - you're not actually reducing anything physical. All the pixels will be exactly the same, the file size in MB will be exactly the same and when the person at the other end comes to print it the results will be exactly the same....assuming they're not stupid enough to print it eight foot square at 77ppi and not tell the printer to make a 6x4" print at which point the ppi will then return to whatever you originally set.

[xpatUSA]

I realize that emailed images are reduced to 72 ppi (or thereabouts) despite whatever the native size of the image might be. I think that I am correct in this assumption.

Sorry, Richard, you are not correct - as others have already said. I will try to add some clarification. The 'size' property of an image is always understood to be expressed in pixels, e.g. 4000x3000px. How big this looks on any output is quite variable. Additionally, when we speak of 'reducing' an image, we understand that it means re-sampling an image to change it's pixel size, e.g. from 4000x3000px to 2000x1500px - a 50% reduction.

As you know, image files have more than just pixel data in them. They also have 'meta-data' in them, sometimes a lot, sometimes not much. Usually, but not necessarily, the meta-data is arranged in a standard format called EXIF containing such stuff as exposure details, lens used, etc. Part of all that stuff is three line items:

X resolution
Y resolution
units of resolution

There is where the camera (for in-camera JPEGs or TIFFs) will put default numbers and it is also where RAW converters will do the same when 'saving as'. There are applications that let you change those numbers.

For viewing on screen at 100% the viewer ignores the EXIF resolution numbers and puts the image up at one screen pixel per image pixel and you see it as approx. 90 dpi depending on your monitors dot pitch. Zooming in or out is done by the viewer - but the image file is not resized for zooming and neither is the resolution metadata changed.

If you open an application e.g. Gimp and tell it to print at 100%, then the metadata value will be used. For example, Sigma uses 180ppi as a default value for my cameras. So if, after editing, my Maltese dog pic comes out as 960x768px it will print out at 960/180 = 5.33" wide by 4.27" wide. Too small? I could use a utility to go in and change the meta-data to, say, 90 ppi, which will double the printed size. But it's easier to just tell the print dialog to print at 200% which effectively does the same thing.

We share text files across our Maltese Rescue California membership using Dropbox. If I place a 240 ppi JPEG file in my Dropbox, will it be 240 ppi when the member opens it.

By now, you should understand that it is not usual to describe a JPEG as "240ppi" because that gives no indication of the size of the image itself. Your statement is true only in that meta-data in the file should not be changed by Dropbox.

There are some files that we need printed at various locations and I want to ensure that the resultant prints are up to standards and not printed from a small emailed file.

Assuming that you are downsizing images to, say, 640x480px to appear embedded in an email message then printing from those by whatever means will not be "up to standards". However, attached files can be quite large. And, if "standards" are for showing a reasonable facsimile of a dog for adoption/purchase, my view would be that a JPEG of 50% quality, intended for printing at 8x10" or less, would not be a large file.

If Dropbox won't do it, how can I send larger sized files via the Internet?

So, I would assume "larger-sized" as being 8x10" or less. Now, you don't know what printer will be used, nor do you know what application will do the printing. Therefore I would decide what ppi I would prefer; perhaps my 180 ppi? Now you take your shot, edit as required and save it cropped & re-sized to 8x180 = 1440px by 10x180 = 1800px, hey presto: a 1440x1800px portrait image. I have just made one such image which came out at ~250Kb - small enough for attachment in quantity to any email, IMHO.



So that's how I would do it, attached to an email, not embedded in the message itself. And of course instruct your recipients what output size in inches or cm to print at.

Or, at ~250Kb per image, could you not continue with Dropbox?

[HenkB]

Just to add one more item. For the purposes of email transmission, large files are considered large by virtue of their file size (expressed in bytes) not physical size (expressed in pixels, inches, or whatever). Today, there are few ISPs that do not allow sizes of 10Mb for attachments. It is possible to generate a 10Mb jpg but not particularly easy. For example, our family Christmas photo measures ~2000 x 3000 pixels at high quality and the file size is under 4Mb. As Ted mentions, the place to reduce file size as opposed to pixel weight is in the Quality setting of your jpg generator. If you are having trouble getting full-size jpgs through via email then the likely reasons may have to do with individual preferences on the various machines or operator error at the various sites. For instance, the Apple Mail program that I use has an inconspicuously placed drop-down that allows you to choose size (Actual, Large, Medium & Small) for transmitting attachments. Other programs may make such choices similarly available. With a maximum file size from a web browser of 10 Gb, Dropbox should be able to accommodate a normal photo of any size or file weight.