yes absolutley

There is no rule.
'Standard' can only exist if there are exceptions.

I have visited 'Paris Photo' fair in November (probably the most important photo fair world wide), far more than half was color.

Show what YOU think is right, and never worry about embarrassing an exhibitor.

No.

Well technically maybe, but almost nobody ever does it well.  If the show is a retrospective, then mixing the two is fine.  If it is a specific project, then it is very, VERY difficult to mix the two without the show looking scattered.

Also, colour is actually a bit more common than black and white these days.  All the cool kids are shooting colour 4x5 or 8x10.

1) YES>  you can mix the two...BUT, the theme or story connecting the pieces needs to be stronger than the distraction of mixing color with B&W.

2) If you are absolutely not 100% comfortable converting to B&W in a way that shows a richness of detail and tonal range, then stick with color.  Nothing is worse than badly converted B&W.

My canon 5d shoots 3744x5616.  I wonder if I should bother to reformat such that the aspect
ratio is 4x5 (or 4/5, whatever)?  This is a one-shot exhibit-- no contest
or anthing like that.  The other guy has a Leica DSLR which also
seems to use 2x3 aspect ratio, so I imagine
if he exhibits with me he will either have the same reformatting problem or
will leave it alone.  He did not mention anything about aspect ratio
to me.  I can probably influence him one way or another.  I have not
done a complete survey of my own submission for this problem but
I anticipate that reformatting for 4x5 would cause a few annoyances
here and there.  I am not sure that I could come up with a complete
reformat because of framing/composition in at least a couple of my favorite photos (I anticipate).

Story? I need to show a story??  yikes!!

I had thrown together some of my better model stuff and landscape
and architecture stuff.  I want it to be approachable, appealing and potentially sellable, without sacrificing too much on whatever else
is left (pure art?).  I actually went out and took a photo of some flowers
at the last moment because I had nothing like that in my entire port
and felt that if some gallery visitor decided they wanted a flower photo
from me they would be out of luck (this will be a long long way from
home).  As I'm typing this I realize I don't have any animals either,
though that might not be such a bad thing since I would prefer to avoid
being too saccharin.

As to poorly converted black and white, I hear you.  I wonder what
poorly converted means.  Maybe someone out there has some pointers
to either good or bad examples, and particularly bad ones with commentary
so I can get a better idea of what to avoid.  For editing, including
desaturating, I'm using PS CS5 and gimp.

Back to the story concern, I had presumed that
the exhibit itself would be in a sense the story.
That is, the exhibit presents a record in photographs
of the world as seen through the lens of my camera
and my mind.  So that (in my original theory) would
permit almost any photo I take to be submitted.

Is this....exhibit theme based?   or just you and this guy get to throw stuff up on wall space?

Rather than worrying too much about whether a photo looks "good enough" because it's color, I'd kinda worry more about an creating an exhibit that works based on theme, execution, presentation, etc.

I'd rather have a coherent exhibition of 15 very good to excellent pieces vs 50 prints of which 50% is crap or nearly so.

Hmm.  By theme do we mean something such as for example, fashion?

If Andy Warhol put up an exhibit of some photos of soup cans,
Empire State Building, and Viva, would it be bad because of lack
of theme?  I do see photographer's stuff hung for display or sale
in banks and restaurants but I am stumped to recall a time
when I stopped to think about whether there was a theme.
I imagine that when I saw photos of disparate types of subjects,
I would have said to myself, "this guy is presenting a personal
worldview through his photos" and then examined each photo
independently of the others.  Would I have been wrong to do
this?  Is a gallery exibit substantially different?

If I present something with one theme (eg fashion or architecture)
only, then it seems to me a danger is that I turn off any visitors
not specifically looking for fashion.

It's not a matter of reformatting - the cameras are inherently different.  But I meant it as a joke, so I wouldn't worry about it

That IS a coherent theme.  The purpose of the entire silkscreen series was to relate art to consumption and consumerism - that's why they are usually shown as a huge series.

Those images all make the same statement, and reinforce each other.  And if you want to get all meta about it, even his self-portraits do that, as he eventually became (and encouraged) the very idea of consumerism that he was originally mocking.

Did you actually read the article?  He shoots in B&W.  What about the article makes you think that going back to the bus station and now concentrating on B&W is the right move for you?

You prepared your prints the way you did because of your style (presumably and hopefully), not because someone in a blog post happens to present a certain way.

When I see a photographers work in a gallery that is very scattered, It feels to me like they have not found their voice yet.  I am disinclined to purchase.

Why?  Why would you compromise your compositions for an aspect ratio?

If you respect him at all, you will not try to influence how he presents his art.  It's not your place to direct him how to crop his pictures.

Do you understand what 4x5 is?  It's large format, not a cropping ratio.  The look is completely different from a 35mm or APS-C frame cropped to a 4x5 ratio.

Are you sure the offer is legit? I ask because there are a TON of scams involving both photographers and models so hopefully this is a legit offer.

Second, try Nik Software's Silver Efex Pro 2 software for b&w conversion. It does a tremendously better job than simply desaturating.

I've seen plenty of color photography exhibits and it seems to me it would be up to the exhibitor to tell you what they want.

The 4x5 or 8x10 in Large format is the size of the film or sensor if using a digital back, not just a ratio for printing it means it can capture a lot more detail than a 35mmX24mm film or sensor which is the size for a 35mm camera or a full frame DSLR.

Yes I did read the article, but the visuals freaked me, perhaps because
he did not address his choice of B&W for a medium, and I had not
checked with trends (other than what is on MM perhaps) before
starting myself.

Hmm...

This is being done overseas on a shoestring budget.  I wonder if
I need to revisit the gallery and oversee the final selection in site
to make sure it does not have that scattered feeling.  I think
I know what you mean.  I have a natural tendency to break with
conventions.  I don't want to be a traitor to my natural tendencies,
but I also sense the value of following your advice, at least up
to a point.  It leaves me wondering if this is a reason (or
an additional reason) to try to go back in person to
arrange to oversee the final installation and be at the opening (yikes).

OK, thanks for the advice, which sounds good.

Sorry, what I meant is cropping my stuff to a 4 by 5 ratio.  Yes, I am concerned
it would affect my look.  If I can stay at 3744x5616 or thereabouts,
that would be both logistically easier and I would not have to be
concerned about the effects of re-cropping on my stuff.

It is legit.

Thanks for the tip on Nik Software, I will investigate.

Thanks.  Interesting... I think I still have vestigial dual vision with Warhol's
stuff.  I recall being very confused when he first came out with it (and
I was not in tune with the artistic side of the world at the time).

Right.  I was glossing over the sensor array size and just focusing
on the ratio when I originally posed my concerns.  Sorry for the confusion.
And of course it has some effect on resolution, maximum print size (or at least
I imagine), etc.

just out of curiosity, is there an actual curator for this exhibit?

how did they become aware of your body of work, were they just cruising MM and found your MM page?