I use Gimp 2.4.7, Acrobat Reader 9 for Linux.

I had to convert a scanned pdf document to text so your howto help me a lot. Thanks for that.

Just a couple of things I made a little diferent:

1. I selected and copied the text image from Acrobat in a new image from Gimp that I previously open with Advanced Option where I specified Grayscale and 200ppi.

2. I Edit > Paste and then scaled the Layer with Layer > Scale Layer until I could see very well the letters and I cleaned the picture out of dots, etc as you recommended.

3. I followed your direction in Image > Mode >Index but I didn't do the threshold thing, just Color > Brightness & Contrast. There I put Brightness at -127 and Contrast al 127 (of course this depends on how good you can see the image).

4. File > Save as... Here I put .tif at the end of my chosen name. Here it ask me to Export and you have to choose Flatten Image.

5. Then as you indicated:

$ tesseract   filename.tif  result

I just want to thank you again.