I am taking pictures in Camera RAW. The camera is a Panasonic DMC-FZ1000 and has 20.1 MP.
I take the SD card from the camera and directly upload my pictures to Lightroom 6. I use Lightroom 6 and Element 13 to edit pictures changing the colors, cropping pictures, etc. Once finished I export the pictures as a TIFF/JPEG file. For some reason when I crop the picture or use color editing, a picture that was once a higher MB reduces to a KB or low MB lower than 4.0 MB. The image quality also decreases; I wanted to print 36X20 inches images and the pictures became very grainy and out of focus/unclear once I tried to enlarge the photos. If I print it 4x6 pictures are clearer. The purpose of Element 13 and Lightroom 6 looks like it gets diminished when I enlarge it to a larger size and the purpose of buying this was to maintain good quality using wonderful photoshop software. Maybe there are ways to improve it so please guide me how to do it.
Here is an example of picture data before I use Lightroom software:
Size 9.75 MB
An example of the data from a picture I used in Lightroom 6 is:
Size 3.74 MB
Look at how gorgeous this image is after using this wonderful software!
When you exported from Lightroom 6, you have obviously instructed Lightroom to reduce the number of pixels in the image to 1000x650.
So, try exporting this photo again, but this time do not check "Resize to Fit" in the export dialog box. Your photo should then be 5472x3648 (or somewhat smaller if you cropped it) and every pixel (or every uncropped pixel if you cropped it) winds up in the exported file.
For a 36x20 inch picture, at 150 DPI, you need an image that is 5000x3000 pixels.
If you are cropping your pictures down to 1000x650 pixels, you don't have enough pixels left to print at your desired size without doing some serious up res'ing.
Alternatively, if you are mistakenly telling LR to export your big pictures as small ones, turning off the "resize to fit" in the export dialog should solve the problem.