I'm starting out with a 7meg jpg file, some adjustments and slight crop and my export is only 700kb. Quality is at 100 and 34,00dpi. I don't print much and this will be a 16 x 20. Will it be OK?
The megabytes of the original file, and the megabytes/kilobytes of the exported file, are irrelevant to the question you asked ... you need to tell use the number of pixels (height x width) of the exported photo.
If you are using Lightroom then you have great print options, exporting and resizing files to use Photoshop or other options to print are probably not beneficial. Have a look at this tutorial from the Lightroom TV website.
The print capabilities in Lightroom are just beyond Photoshop.
I exported it two ways. The first I did not specify a size only the max of 34000dpi. The second I did the size in inches (16 x 20) vs pixels.
You didn't answer the question. Even though you didn't specify the size in the export dialog box, the exported picture has a width and height measured in pixels. That is what we need to know to answer your question.
By the way, I have never seen a use for 34000dpi (probably you meant ppi). There are a few printers that need 1200 ppi or 600 ppi, most need 300 ppi, and for a 16x20 you might be able to get away with fewer ppi.
Thanks for the dpi info. I thought I needed 600 or so but I looked up the max and specified that. As I mentioned I was not sure what the pixel measured size would be for 16"x20" so I speced that out in inches. What should it be?
A photo that is 442x552 cannot possibly be printed at a reasonable quality level at 16x20 (in fact it won't even print well at 4x6). Which brings up the question, what is the size in pixels (height by width) of the cropped photo that you exported?
In the export dialog box, you would need to specify that you want 240 pixels per inch, you would want to specify a width and height of 16x20 inches, and unclick "don't enlarge". BUT ... if the original cropped photo was relatively small (please tell us the dimensions, as I asked in the first paragraph), it is unlikely you will ever get a quality print from a small original.
Sorry I was missunderstanding your question, I thought you wanted the size of the exported file. My cropped file before export is 3321 x 4152. The original that I cropped down from was 3456 x 5184. I'll go play with the export settings some more. I believe I want the exported image at 3321 x 4152 for a 16" x 20" print. But that means my pixels per inch will be about 207.
No you didn't misunderstand. I asked two distinct questions.
If you have a 3321x4152 image, then you can print at 16x20 at 207.6 ppi. This may be sufficient to get decent quality, as 16x20 would be viewed from a short distance, further away than you would view a 4x6. However, if you export the photo at 442x552, then you will get lousy quality. You have to export at the 3321x4152 size, or even larger if you want. You have to specify the width and height and ppi in the export dialog box, as I described above.
OK, so I am getting closer. I did an export at 16 x 20 and 207pixels per inch and got a file that is 3312 x 4140 and 207 pixels per inch. I think I have a rounding error going on there. I then tried another export at 16 x 20 and 240 pixels per inch. That didn't work, LR just went into an export mode for a long time. I finallt cancelled the export. I'm guessing that is not possible so LR didn't know what to do. I am surprised it did not give me some kind of error. Now, will the 3312 x 4140 work or should I fine tune the export some more(207.5 pixels per inch)?
I then tried another export at 16 x 20 and 240 pixels per inch. That didn't work, LR just went into an export mode for a long time. I finallt cancelled the export. I'm guessing that is not possible so LR didn't know what to do.
Of course Lightroom can do this export. I don't know why it took so long (about how long did it take before you cancelled?)
Now, will the 3312 x 4140 work or should I fine tune the export some more(207.5 pixels per inch)?
Didn't I answer this already?
There's no practical difference between 207 ppi and 207.5 ppi, no one will ever know the difference.
If I try to print a 3321 x 4152 pixel file at 16" x 20" and 240 pixels per inch there is not enough file size, right? I think that is why LR just sat there. I probably gave it 10 minutes before I shut it down.
I appreciate all your help. I think I am all set now.