Rectify -- and I get nasty cuts across the image

[greenmorpher]

hello folks

Bab Tullis came up with an image transformation he did in LR 3 and LR 4 (beta) on the DPReview Micro Four Thirds forum.

http://forums.dpreview.com/forums/read. ... e=40327585

I wondered whether I could make any impression on him transforming his original in PhotoLine. It actually looked moderately straightforward to me (always allowing for the fact that I am pretty hopeless at this sort of stuff -- particularly when it comes to correcting color).

So I saved off his "original" (actually a much reduced JPEG, of course -- his original would have been three or four times bigger in pixel count and would have been around 4 MB (as an OOC JPEG) rather than the <300 KB of the file here) and had a go. I think it came up pretty well pretty simply in PL, at least to this point -- I was not yet finished, however, when I noticed the nice, orderly broken lines in the pillars following rectification (Filters > Digital Camera > Rectify). Diagonal slicing.

What's going on here? Is this an artifact of working with a much reduced file or what? I've rectified quite a few pix in PL (buildings I stand near to photograph have an uncanny inclination to lean away from me -- is it bad breath or something?) and never seen this before.

Cheers, geoff

http://pngtimetraveller.blogspot.com/20 ... an-in.html

[Ron C]

Your result is consistent with having antialias turned off.

[Hoogo]

Ron is right, the result depends on the antialiasing-button. Didn't know that

Without antialiasing that rectify-tool is using nearest neighbor. Good for graphics, good for sharpness, but not that good for pictures and edges. An option as it is used for scaling would be nice.

The normal rectangular lasso does not care about the antialiasing-button. Draw a rectangular lasso, hold down CTRL when moving its corners, check the "straighten"-checkbox and crop. But that way everything outside the selection is lost.

[greenmorpher]

Anti-aliasing button? There is no anti-aliasing button that I can see. So actually there is no anti-aliasing available for rectify.

I must have got away with it in my own images because I had the full image -- 3500-4000 horizontally, for example, instead of 1000 or so.

Hello Hubers!!! We need anti-aliasing working with Rectify!

Actually, now I'm looking about it, I remember running into exactly the same problem in Canvas years ago. The answer was to enlarge the image, do the rectification, then shrink the image.

AND IT WORKS!!! See the attached.

But that's a workaround, like the one using the selection tool you mention, Hoogo. That not the stuff we should be doing in a real editor which has a real Rectify tool. If it has to be done, it should be done invisibly by the tool and we should just see the result.

Cheers, geoff

[greenmorpher]

So I have an answer to a problem that might come up for me in PL, but I am not going to post a PL-based solution to the DPReview forum -- which is what I had planned to do -- when it involves a half-arsed step like that. It must be fixed. I scaled it up to 50 cm width at 300 dpi by the way, and PL handled the rectification of that image with its usual speed and grace. That responds somewhat to the earlier discussion I instigated about PLs asbility in upscaling images.

Cheers, geoff

[bkh]

Rectify works for me. Just make sure global antialiasing is switched on (in the General Toolbar), or switch on antialiasing for the layer (in the Attributes panel). Antialiasing should be on by default, afaik. Btw., I prefer the crop tool to rectify images because it works like distorting layers – you drag the corners until vertical lines are vertical.

Cheers

Burkhard.

[Hoogo]

Anti-aliasing button? There is no anti-aliasing button that I can see. So actually there is no anti-aliasing available for rectify.

At least there is no button in the dialog... The standard-button for antialiasing in the normal toolbar is used. The button with that pixely black line on it.

[OldRadioGuy]

ButtonLocation.png

Anti-aliasing button? There is no anti-aliasing button that I can see. So actually there is no anti-aliasing available for rectify.

Cheers, geoff

Geoff, here's the location of the Antialias Button, at least on my system. I don't remember if it's the default because I long ago customized my toolbars.

Bob

[greenmorpher]

Ah, yes, that's it. I don't have the toolbar open, you see.

Still, should have this in the tool dialog. It is there for some other stuff.

Thanks bob, burkhardt and hoogo.

Cheers, geoff

[greenmorpher]

Should I have anti-aliasing turned on by default for all pix so it applies when I resize? I rather thought the Lanczos process would take care of this.

How is it set 'on' by default in any case? I see it is available in the Attributes panel, but presumbly that applies only to the open file.

The next step -- I've mimicked Bob's editing pretty much except for the sky. I need to desaturate it. I've just totally lost how I'm to do a selective desaturation (I've done it before, but rarely). Help, please.

Cheers, geoff

[Hoogo]

I would try "Tool > Color > Hue/Saturation". There you can select the "range", blue seems to be just fine for this picture. Desaturate as you like.

For other pictures you might find that there are quite some shades of blue. Some you would like to change, others should be preserved. Then you could fine-tune the definition of blue with the 4... triangles(??) between the colorful gradients at the bottom.

Finally, press OK, or try the smaller "Create Adjustment layer" left of the OK-Button.

EDIT:
I've added a tiny test-picture with such a hue-saturation-adjustment-layer. Double-click on the layer, select the blue range and play with the 4 triangles.