M
mlgh
Don said:
For you more than any I think Don! ....Anybody mentions the "V" word
and off you go!
mlgh
For you more than any I think Don! ....Anybody mentions the "V" word
and off you go!
mlgh
H
Hecate
Don isn't the only person who considers Vuescan to be nothing but a
rolling beta, I can assure you.
--
Hecate - The Real One
(e-mail address removed)
Fashion: Buying things you don't need, with money
you don't have, to impress people you don't like...
L
Linda
Don said:
Thanks for the encouragement. I was getting a bit frustrated. I tried
some more auto exposure tests as Kennedy suggested. I also tried Epson
scan per suggestions but haven't tried
"When the scan starts hit the "Cancel" button, which will enable full
manual mode. The exposure control is then available by selecting the
tools button."
per Kennedy's instruction. I will try that tonight or tomarrow. It's
getting late for me.
I posted my problem on a web page to try to illustrate what I'm talking
about. Actually it's three pages because it's all graphics and didn't
want to bog anyone down. I left out the pastels I mentioned in the OP
because my big problem now seems to be exposure.
I've checked my gamma settings and file format (adobe RGB 1998) to make
sure it was consistent. I think I've got it right but intend to
recheck.
The link to the page is
http://home.nc.rr.com/cullenrep/positive.html
I'm curious to know if this explains better what's going on and if you
all think I'm on the right track.
Thanks, Linda
D
Don
Thank you for proving my point!
Instead of helping the OP (as I did!!) or stating any facts, your
*only* concern was to sneak in a snide comment with a baseless
personal attack.
Which is exactly how the rabid "V sect" is behaving around here.
Don.
D
Don
Don isn't the only person who considers Vuescan to be nothing but a
rolling beta, I can assure you.
That's an improvement from Vuescan's usual "alpha" status! ;o)
Don.
D
Don
OK, I think things may be becoming much clearer now. I - for one -
failed to notice you were using a flatbed! I thought you used a film
scanner!
First of all, flatbeds don't usually have an explicit exposure
setting. So no wonder you couldn't find it!
Secondly, looking at the scans it appears you didn't turn on
backlighting! A bit of background (please ignore if you know it
already)...
Flatbeds work on the basis of reflected light. In other words, the
light comes from the scanner itself, it bounces of the document on top
and then it gets registered by the CCD array below to produce a scan.
However, when you scan slides, this doesn't work. All you get is a
reflection of the film surface. And there is no image to speak of on
the film surface. The image is in the film itself and to see it you
have to project light through it.
To do this, flatbeds have backlighting - usually built into the lid.
Sometimes, this is hidden behind (covered with) a movable strip. So
before scanning film on a flatbed you first need to remove this.
Next, many (all?) flatbed scanners don't turn on this light all the
time (because it would interfere with regular, reflective, scanning)
so you need to get this light going. Many times you actually
physically have to connect a cable to the lid (usually next to the
hinge) to supply power to the lamp in the lid.
Anyway, I may way off base here, so let's see first if this makes any
sense so far.
Don.
L
lenny
Don said:
I WISH.
Yeh, I've only found auto exposure.
I did know this and do remove the strip when scanning slides
How many times when something doesn't work is it merely a bad
connection? Often checking the connections fixes the problem.
Unfortunately not this time. I disconnected the cable to the lid and
made sure it was clean and reconnected it. I have the software set to
transparency and positive since it's a slide. I also lifted the lid
while scanning to make sure the light in the lid was on and working
while scanning. It is. This was one of my thoughts that maybe the light
was burnt out or maybe it's not bright? enough. I tried Kennedy's
suggestion of canceling the scan in Epson Scan and it didn't work but I
probably did something wrong, so I'll read and try again.
I guess I'm just stumped. But not beat_yet!
You make sense. Do I?
Linda
K
Ken Weitzel
lenny said:
Hi...
I'm just a lurker; pardon me commenting, please.
Can't help wondering why you have the gamma set
at 1 ? Wouldn't you prefer at least 1.5 or even
1.75 ?
And I too use an Epson, and if I click cancel during a
scan the only thing that happens is the twain exits
Oh, one more thing. You are using the slide holder,
right? And you have it correctly set in the bed so
that the white arrow on the template points to the
matching arrow on the bed frame, so the calibration
slot is free and where it should be?
Take care.
Ken
K
Kennedy McEwen
lenny said:
Just for clarification. Using the Epson driver, if it starts in full
auto mode then hit cancel during the initial pass. That will bring up a
dialog at the end of the initial pass with the following options:
"Close" - which will close the Twain interface
"Manual Mode" - which will switch to fully manual mode (which then has a
control to return to full auto if required)
"Scan" - which continues the scan in full auto mode according to the
image that has been picked up on the first pass.
In the full manual mode, the exposure control is the top control in the
toolbox. The toolbox itself will be greyed out until you have made a
preview scan.
D
Don
Due to all the software bugs we (including yours truly!) are
conditioned to usually focus on the software, but often times it's
something as simple as the darn thing not being plugged in or even
turned on! Believe me, I've had some gems like that!
That's the spirit! We'll get to the bottom of this!
Yup! The problem now is I'm not familiar with Epson but Ken has a very
good point with that "calibration slot". Let us know how that goes.
Don.
D
Don
Not at all! The more the merrier!
I did mention gamma as one of the possible causes (as well as a
profile mismatch) and Linda says both are correct. However, I'm not
familiar with Epson so you can probably offer better concrete advice.
That sounds like a very important point! If that "calibration slot" is
obstructed it would certainly explain a lot!
Don.
L
Lenny
Hi KenHi...
I'm just a lurker; pardon me commenting, please.
Can't help wondering why you have the gamma set
at 1 ? Wouldn't you prefer at least 1.5 or even
1.75 ?
And I too use an Epson, and if I click cancel during a
scan the only thing that happens is the twain exits
Oh, one more thing. You are using the slide holder,
right? And you have it correctly set in the bed so
that the white arrow on the template points to the
matching arrow on the bed frame, so the calibration
slot is free and where it should be?
Take care.
Ken
I think I have my gamma set at 1.8. I'm on a Mac. Did you see something
to indicate I missed something? I'll look again.
The calibration slot is a good point. I really didn't realize it was
there until a few days ago. However I have always put the slide holder
in correctly and have even scanned without it.
Thanks, Linda
K
Ken Weitzel
Lenny said:
Hi...
Forewarned is forearmed... I'm not only getting long
in the tooth but also a stroke victim... easily confused,
awful forgetful, and not at all eloquent, so take what
I say with a grain of salt
Having warned you - the gamma on your mac set at 1.8 is
(default) correct, as it should be (2.2 for windows folks)
That however is the monitor. It ensures that we can
share what each other have photographed/scanned with each
other, and all see a reasonably close approximation of
each others stuff. I say default - going further with
for instance the spyder stuff is difficult, time consuming,
and very expensive.
Bottom line, leave your *monitor* gamma where it is
That's the monitor gamma. The slide itself isn't at all
linear, and requires gamma correction. A whole different
kettle of fish
For the slide, I'm sure that I saw and was surprised that
your histogram captures showed the gamma at the default
of 1.0; where Epson's default put it.
Fortunately, digital experimentation is cost free and
pretty painless; so try this.
Go back to where you were when you captured that
histogram. Let auto set the white points and black
points if you wish, or do it yourself manually.
You'll see three arrows - 'grab' the middle one,
drag it to the left to change the gamma number below
it to 1.5 or perhaps 1.8. You'll see the preview
screen change as you drag and hopefully like the
results a bit better.
Let us know how it works out for you. Whew! You were
warned
Take care.
Ken
H
Hecate
Highly unlikely. Whilst that was true in the past, nearly all
monitors are now set at gamma 2.2. So unless it's been changed by the
OP, 2.2 is what he has.
--
Hecate - The Real One
(e-mail address removed)
Fashion: Buying things you don't need, with money
you don't have, to impress people you don't like...
L
Linda
Ken Weitzel said:Hi...
Forewarned is forearmed... I'm not only getting long
in the tooth but also a stroke victim... easily confused,
awful forgetful, and not at all eloquent, so take what
I say with a grain of salt
Having warned you - the gamma on your mac set at 1.8 is
(default) correct, as it should be (2.2 for windows folks)
That however is the monitor. It ensures that we can
share what each other have photographed/scanned with each
other, and all see a reasonably close approximation of
each others stuff. I say default - going further with
for instance the spyder stuff is difficult, time consuming,
and very expensive.
Bottom line, leave your *monitor* gamma where it is
That's the monitor gamma. The slide itself isn't at all
linear, and requires gamma correction. A whole different
kettle of fish
For the slide, I'm sure that I saw and was surprised that
your histogram captures showed the gamma at the default
of 1.0; where Epson's default put it.
Yeh, you did!
I had no idea that the middle arrow was for gamma. I'd played around
with it and was aware of the changes it made but didn't know what it
was. Everything I'd read was about black and white points. That's so
good to know. Helps me understand more of what I read from others.
Let us know how it works out for you. Whew! You were
warned
Going back, per your suggestion, and discussing it with ol' Lenny, I
think it's a correction better made by him in PS after the scan. For
now anyway.
Thanks, that was very helpful.
Linda
D
Don
I don't know Epson software but that value in the middle (for Levels
in Photoshop, for example) is usually displayed as 1.0 just as a
starting point. Even though the middle slider can be used to set the
gamma, the initial value displayed there does not indicate current
gamma, as such, because Levels doesn't know the gamma of an image
beforehand.
Here's a little test to explain what I mean. Load an image in PS and
open the Levels dialog box. It will show 1.0 so change the middle
value to 2.2 (or 1.8, or whatever) and click on OK. After the editing
is complete and the Levels dialog closes, open it once more, and it
will show 1.0 again even though you just applied a change!
Therefore, I strongly suspect ("global") gamma is set somewhere else
in the Epson software. There is usually an explicit reference to which
gamma should be used when scanning.
There must be some sort of "Preferences" option in Epson software.
That's where I would look for the gamma setting.
Don.
M
mlgh
I have Epson Twain Version 5.51E downloaded from Epson about a year
ago, although I use it with an old(ish) 1200S SCSI flatbeb.
In the center left of the interface is a row of buttons, the left hand
one with a spanner on it. Clicking this opens "Image Controls"
including both Exposure and Gamma. The settings displayed being those
of the last preview.These settings will be arrived at automatically
unless Auto Exposure is switched off.
Below the "Spanner" button is a button labelled "Configuration" which,
under the Color Tab allows Auto exposure to be switched off (unchecked)
and there is also a box for Display Gamma (different to the Image
Controls one).
mlgh
L
linda
Don said:
So Don
I've played around with the "little triangle in the middle" and see
what changes it makes. I thought it had to do with middle grays. Not
sure where I got that.
What is it for and does it have a name other than "the little triangle
in the middle"
thanks Linda
L
linda
Kennedy McEwen said:
Thanks for the clarification. I missed the "full auto mode" part. But
like Ken "if I click cancel during preview (the first pass) or scan the
only thing that happens is the twain exits. But Migh says he has Epson
Twain Version 5.51E. My Epson Scan is in a folder
Preferences->Twain->Epson Scan. Epson Scan being the application. The
version is 2.00A. Which means I probably need to make a trip to the
Epson site and see if there are upgrades to the software that came with
this scanner (epson 4870)
Thank You, Linda
F
false_dmitrii
linda said:
If the end sliders control "black point" and "white point", the middle
triangle is the "gray point". In a 8-bit-per-channel RGB image, the
middle triangle determines where all three channels hit the midpoint
level of 128 (or is it 127?) and combine to form "middle" gray. If you
slide it toward the white point, it squeezes all the data lighter than
the old gray point into a smaller range. At the same time, it
stretches out the darker data. In an 8bpc image, moving the slider too
far will quickly create gaps between lightness levels in the darker
data and lead to visible posterization. Since a 16bpc image has
additional "invisible" data between each 8-bit value, it can stretch
farther before big gaps appear.
The middle triangle doesn't have to set a "gray" point. It's just the
midpoint between the brightest and darkest values. You can set
different values for red, green, and blue channels independently, which
will position the overall gray point somewhere in between. You can
also use it in individual HSL or LAB channels to control something else
entirely. Note that it's always "gray" in the sense that it
corresponds to gray 128 in the grayscale view of an individual channel.
My understanding has been that moving the "gray point" for the
composite image is equivalent to changing the gamma curve. Bear in
mind that I've been picking all this up as I go along and haven't made
the minimal effort needed to get a solid grasp on what exactly gamma
*is*. (Ratio of lighter-than-gray to darker-than-gray?) It just makes
sense that as you stretch the data in one direction and compress it in
the other, you're creating the same non-linear distribution of data
that gamma values other than 1 reflect.
(Also notice that gray 128 is the halfway point of the typical Curves
control. Moving the histogram gray slider back and forth can have
about the same effect on the "curve" of the image lightness
distribution as moving the midpoint of the Curves line up and
down...depends on how the particular Curves tool operates.)
But Don is correct that the histogram's gamma slider isn't usually the
way to set the initial gamma value of the image. There should be a
setting somewhere to control whether 48-bit data is output at linear
gamma 1 or non-linear gamma 2.2 (and maybe other custom values). If
not, it's quite possible the image is being saved at gamma 1 and needs
to be adjusted either via the graypoint control or through an image
editor's gamma options. I've been neglecting my scanners horribly and
haven't run Epson Scan in quite some time...I'll have to hook up the
scanner to get a look at the software options again.
I remember www.scantips.com as being helpful when I was trying to learn
what the histogram was all about. There are some other good resources
that I can't recall offhand but you might be able to track down through
Google. Your Photoshop expert ought to be able to help you out with
some of this as well.
Also, you might consider posting some screenshots of your Epson Scan
settings with your previously posted negative scans. It would help
*me*, if no one else, spot anything odd.
false_dmitrii