Manatee

How to convert a JPEG or PNG to TIFF on a Mac

· 6 min read

To convert a JPEG or PNG to TIFF on a Mac, open the image in Preview, choose File, Export, set Format to TIFF, and save. For a folder of images, use the sips command in Terminal or drop them into Manatee and choose TIFF. The conversion itself is simple; the part that trips people up is the “300 dpi” requirement that usually comes with the request, which is covered below.

What converting to TIFF does and does not do

TIFF is a lossless format. Once an image is a TIFF, opening and saving it again does not wear it down, which is why printers, publishers, journals and archives ask for it.

Two things are worth knowing before you start.

  • A JPEG does not get better. JPEG compression has already discarded some detail, and converting to TIFF cannot bring it back. What the TIFF does is stop any further loss. If you have a higher quality source, such as the camera’s raw file or the original export, start from that.
  • The file gets much bigger. A TIFF stores every pixel, so expect a file several times the size of the JPEG. That is normal. If the size becomes a problem for sending, see the last section.

A PNG is already lossless, so PNG to TIFF changes the packaging and nothing else. Lossy versus lossless explains the difference in more depth.

Convert one image in Preview

  1. Double-click the image so it opens in Preview.
  2. Choose File, Export.
  3. Set Format to TIFF.
  4. If a Compression menu appears, choose LZW for a smaller file. LZW is lossless and widely accepted. Choose None only if the recipient asks for an uncompressed TIFF.
  5. Give the file a name, pick a folder, and click Save.

The original JPEG or PNG stays as it was.

Convert several images in Preview

  1. Select all the images in Finder and open them together, so they appear in one Preview window with thumbnails in the sidebar.
  2. Click a thumbnail, then press Command-A to select them all.
  3. Choose File, Export Selected Images.
  4. Click Show Options, set Format to TIFF, and choose a destination folder.

A note on Finder: the Quick Actions, Convert Image command on the right-click menu offers JPEG, PNG and HEIF only. It cannot make TIFFs, so use one of the other routes.

Convert a whole folder in Terminal

sips is part of macOS and converts in one line. For a single file:

sips -s format tiff -s formatOptions lzw photo.jpg --out photo.tiff

For every JPEG in a folder, written into a new folder so nothing gets mixed up:

mkdir ~/Desktop/TIFF
sips -s format tiff -s formatOptions lzw ~/Desktop/Figures/*.jpg --out ~/Desktop/TIFF

Change *.jpg to *.png for PNG files. Leave out -s formatOptions lzw if you need uncompressed files.

Convert a batch with Manatee

If you would rather not use Terminal, or the images are a mix of formats, Manatee handles the batch in its window.

  1. Open Manatee and choose Convert.
  2. Drop in the images or the folder. JPEG, PNG, HEIC, WebP, camera raw files and many other image types are accepted, so a mixed folder is fine.
  3. Choose TIFF as the target.

Each TIFF is written next to its original, and the original is never modified. Everything runs on your Mac, with no uploads and no account, which matters when the images are unpublished figures or client work. Manatee is free for 24 hours with every feature, then $9 once.

One limit to be clear about: converting changes the file format. It does not change the color mode. If a printer specifically requires CMYK, that is a separate color conversion, best done by the print shop or in a professional image editor. Many printers prefer to receive RGB and convert it themselves, so ask before assuming.

What “300 dpi” actually means

Submission guidelines often say “TIFF, 300 dpi”. The dpi figure is not a quality setting. It is a label stored in the file that says how many pixels to print per inch, and what matters is whether the image has enough pixels for the size it will be printed at.

The arithmetic is short: pixels divided by dpi gives inches. An image 2400 pixels wide, printed at 300 dpi, is 8 inches wide. An image 900 pixels wide is only 3 inches wide at 300 dpi, whatever label it carries.

To check and set it in Preview:

  1. Open the image and choose Tools, Adjust Size.
  2. Uncheck Resample image. This is the important step: it tells Preview to keep every pixel and change only the label.
  3. Type 300 in the Resolution box, with the unit set to pixels/inch.
  4. Read the Width and Height, shown in inches or centimeters. That is how large the image can print at 300 dpi.
  5. Click OK, then export as TIFF.

In Terminal, the same label can be set on a TIFF you have already made:

sips -s dpiWidth 300 -s dpiHeight 300 figure.tiff

Unlike the conversion commands above, this one changes the file in place, so run it on the new TIFF, not on your only copy of something.

If the print size comes out smaller than you need, the image does not have enough pixels. Leaving Resample image checked and typing a larger size will produce a file that passes an automated check, but it only invents pixels in between the real ones, and the print will look soft. The honest fixes are to find a larger original, export the chart or figure again at a larger size from the app that made it, or print it smaller.

Transparency and size

Two details sometimes cause a rejected file.

Transparency. A PNG with a transparent background becomes a TIFF with a transparent background. Some print and publishing systems expect a solid one. If yours does, flatten the image onto white first; how to flatten a transparent PNG shows the idea, and you can then make the TIFF from the flattened version.

Size. TIFFs are large. An uncompressed TIFF shrinks noticeably when you zip it; one saved with LZW barely does, because it is already compressed. If the files are too big for email, send a link from a file sharing service you already use, and check the limits in email attachment size limits by provider.

Questions

Is TIFF better quality than JPEG? A TIFF made from a JPEG has the same quality as that JPEG, in a much larger file. TIFF is better as a working and delivery format because saving it again loses nothing.

LZW or no compression? LZW, unless you are told otherwise. It is lossless, so the pixels are identical, and the file is smaller. A few older systems want uncompressed TIFFs, and their guidelines will say so.

Should the file end in .tif or .tiff? They are the same format. If a submission system insists on one spelling, rename the file in Finder; nothing inside it needs to change.

I need to go the other way. How? See how to convert a TIFF to JPEG or TIFF to PNG.