Sharp images becomes unsharp

[beate27892411eif9]

I'm working with a film in Premiere, using a lot of still images, among them, an extremely detailed map (engraving), which has an original size on 24 000 x 16 000 pixels, 72 dpi. I have downscaled it to the half in Photoshop. I want to zoom into it, so I need high resolution. However, it doesn't look good in Premiere. And, when I export the image in Quicktime, Apple ProRes 422 HQ, which is the format for the rest of the film, the image becomes blurry. 

If I downscale it more, to 3000 x 2000 the result is the same, it looks bad. How can I resolve the issue? 

[Ann Bens]

Make sure your images are set to Set to Framesize and not Scale to Frame Size.

The latter will reduce image quality on scaling up (as in zooming in).

To what resolution did you export?

[beate27892411eif9]

Thank you for your reply. I scale the images manually, so that I get them exactly as I want. Then I export in 1920 x 1080. 

[Zwea]

Your default setting is probably set to Scale to Frame Size.

Preferences > Media > Default Media Scaling

[beate27892411eif9]

The default media scaling is "none".

[beate27892411eif9]

The reason is, sometimes I want to zoom into the picture, other times I want to avoid the white frame around some photos.