How can I to export files in jpg format from Ligthroom 4.3 to Photoshop CS6 and transform them to tiff format and 300 pixels of resolution?
When you export your photograph you must do scrool down on export a file and file settings.
I hope help you
Right click on the selected image or group of selected images and select "Edit In" and look for the entry PS CS6. As for making them Tiff files and at a certain resolution you do that in the LR Preferences under the External Editor tab.
No need to Export as JPG and then convert that exported JPG to a Tiff. It can be done all at once with No JPG in the middle.